Description of problem:
I have cntlmd setup to proxy for my localhost and I can't make mock work with it.

Version-Release number of selected component (if applicable):
mock-1.1.9-1.fc14.noarch

How reproducible:
Every time

Steps to Reproduce:
1. Install mock
2. Configure mock's proxy settings as per http://fedoraproject.org/wiki/Extras/MockTricks#Proxy_Configurations
3. Try to build a package with mock
  
Actual results:
    [adam@server ~]$ mock -v -r epel-5-x86_64 --init
    INFO: mock.py version 1.1.9 starting...
    State Changed: init plugins
    DEBUG: ensuring that dir exists: /var/cache/mock/epel-5-x86_64/yum_cache/
    INFO: selinux enabled
    State Changed: start
    DEBUG: mock final configuration:
    DEBUG: scm: False
    DEBUG: resultdir: %(basedir)s/%(root)s/result
    DEBUG: legal_host_arches: x86_64
    DEBUG: dist: el5
    DEBUG: internal_setarch: True
    DEBUG: scm_opts: {'write_tar': False, 'svn_get': 'svn co file:///srv/svn/SCM_PKG/SCM_BRN SCM_PKG', 'method': 'git', 'git_get': 'git clone SCM_BRN git://localhost/SCM_PKG.git SCM_PKG', 'cvs_get': 'cvs -d /srv/cvs co SCM_BRN SCM_PKG', 'ext_src_dir': '/dev/null', 'spec': 'SCM_PKG.spec'}
    DEBUG: use_host_resolv: True
    DEBUG: more_buildreqs: {}
    DEBUG: createrepo_command: /usr/bin/createrepo -d -q -x *.src.rpm
    DEBUG: yum.conf:
    [main]
    cachedir=/var/cache/yum
    debuglevel=1
    logfile=/var/log/yum.log
    reposdir=/dev/null
    retries=20
    obsoletes=1
    gpgcheck=0
    assumeyes=1
    syslog_ident=mock
    syslog_device=
    proxy=http://localhost:3128/
    # grub/syslinux on x86_64 need glibc-devel.i386 which pulls in glibc.i386, need to exclude all
    # .i?86 packages except these.
    exclude=[1-9A-Za-fh-z]*.i?86 g[0-9A-Za-km-z]*.i?86 gl[0-9A-Za-hj-z]*.i?86 gli[0-9A-Zac-z]*.i?86 glib[0-9A-Za-bd-z]*.i?86
    # repos
     
    [core]
    name=base
    mirrorlist=http://mirrorlist.centos.org/?release=5&arch=x86_64&repo=os
     
    [update]
    name=updates
    mirrorlist=http://mirrorlist.centos.org/?release=5&arch=x86_64&repo=updates
     
    [groups]
    name=groups
    baseurl=http://buildsys.fedoraproject.org/buildgroups/rhel5/x86_64/
     
    [extras]
    name=epel
    mirrorlist=http://mirrors.fedoraproject.org/mirrorlist?repo=epel-5&arch=x86_64
     
    [testing]
    name=epel-testing
    enabled=0
    mirrorlist=http://mirrors.fedoraproject.org/mirrorlist?repo=testing-epel5&arch=x86_64
     
    [local]
    name=local
    baseurl=http://kojipkgs.fedoraproject.org/repos/dist-5E-epel-build/latest/x86_64/
    cost=2000
    enabled=0
     
     
    DEBUG: cleanup_on_failure: False
    DEBUG: plugins: ['tmpfs', 'root_cache', 'yum_cache', 'bind_mount', 'ccache', 'selinux', 'scm']
    DEBUG: chrootuid: 500
    DEBUG: root_log_fmt_str: %(levelname)s %(filename)s:%(lineno)d: %(message)s
    DEBUG: state_log_fmt_str: %(asctime)s - %(message)s
    DEBUG: chroothome: /builddir
    DEBUG: basedir: /var/lib/mock
    DEBUG: internal_dev_setup: True
    DEBUG: macros: {'%_rpmfilename': '%%{NAME}-%%{VERSION}-%%{RELEASE}.%%{ARCH}.rpm', '%_topdir': '/builddir/build'}
    DEBUG: version: 1.1.9
    DEBUG: online: True
    DEBUG: build_log_fmt_name: unadorned
    DEBUG: chrootgid: 487
    DEBUG: files: {}
    DEBUG: rpmbuild_arch: x86_64
    DEBUG: log_config_file: logging.ini
    DEBUG: rpmbuild_timeout: 0
    DEBUG: cleanup_on_success: False
    DEBUG: chroot_setup_cmd: install buildsys-build
    DEBUG: useradd: /usr/sbin/useradd -o -m -u %(uid)s -g %(gid)s -d %(home)s -n %(user)s
    DEBUG: root_log_fmt_name: detailed
    DEBUG: chroot_name: epel-5-x86_64
    DEBUG: plugin_conf: {'scm_enable': False, 'yum_cache_opts': {'max_metadata_age_days': 30, 'root': 'epel-5-x86_64', 'basedir': '/var/lib/mock/epel-5-x86_64', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'online': True, 'cache_topdir': '/var/cache/mock', 'max_age_days': 30, 'dir': '%(cache_topdir)s/%(root)s/yum_cache/'}, 'scm_opts': {'basedir': '/var/lib/mock/epel-5-x86_64', 'root': 'epel-5-x86_64', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'cache_topdir': '/var/cache/mock'}, 'bind_mount_opts': {'dirs': [], 'basedir': '/var/lib/mock/epel-5-x86_64', 'root': 'epel-5-x86_64', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'cache_topdir': '/var/cache/mock'}, 'root_cache_enable': True, 'selinux_opts': {'basedir': '/var/lib/mock/epel-5-x86_64', 'root': 'epel-5-x86_64', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'cache_topdir': '/var/cache/mock'}, 'ccache_opts': {'basedir': '/var/lib/mock/epel-5-x86_64', 'max_cache_size': '4G', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'cache_topdir': '/var/cache/mock', 'root': 'epel-5-x86_64', 'dir': '%(cache_topdir)s/%(root)s/ccache/'}, 'bind_mount_enable': True, 'selinux_enable': True, 'yum_cache_enable': True, 'tmpfs_enable': False, 'tmpfs_opts': {'basedir': '/var/lib/mock/epel-5-x86_64', 'required_ram_mb': 900, 'cache_topdir': '/var/cache/mock', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'max_fs_size': None, 'root': 'epel-5-x86_64'}, 'ccache_enable': True, 'root_cache_opts': {'compress_program': 'pigz', 'extension': '.gz', 'root': 'epel-5-x86_64', 'basedir': '/var/lib/mock/epel-5-x86_64', 'cachedir': '/var/cache/mock/epel-5-x86_64', 'cache_topdir': '/var/cache/mock', 'max_age_days': 15, 'dir': '%(cache_topdir)s/%(root)s/root_cache/'}}
    DEBUG: config_paths: ['/etc/mock/site-defaults.cfg', '/etc/mock/epel-5-x86_64.cfg']
    DEBUG: build_log_fmt_str: %(message)s
    DEBUG: state_log_fmt_name: state
    DEBUG: plugin_dir: /usr/lib/python2.7/site-packages/mock/plugins
    DEBUG: clean: True
    DEBUG: createrepo_on_rpms: False
    DEBUG: cache_topdir: /var/cache/mock
    DEBUG: root: epel-5-x86_64
    DEBUG: target_arch: x86_64
    DEBUG: Unsharing. Flags: 131072
    State Changed: lock buildroot
    State Changed: clean
    DEBUG: remove tree: /var/lib/mock/epel-5-x86_64.tmp
    INFO: chroot (/var/lib/mock/epel-5-x86_64) unlocked and deleted
    State Changed: unlock buildroot
    State Changed: init
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/result
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/result
    State Changed: lock buildroot
    Mock Version: 1.1.9
    INFO: Mock Version: 1.1.9
    INFO: Mock Version: 1.1.9
    DEBUG: rootdir = /var/lib/mock/epel-5-x86_64/root/
    DEBUG: resultdir = /var/lib/mock/epel-5-x86_64/result
    INFO: enabled root cache
    DEBUG: ensuring that dir exists: /var/cache/mock/epel-5-x86_64/root_cache/
    INFO: enabled yum cache
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/cache/yum
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/cache/yum
    State Changed: cleaning yum metadata
    INFO: enabled ccache
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/tmp/ccache
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/tmp/ccache
    DEBUG: ensuring that dir exists: /var/cache/mock/epel-5-x86_64/ccache/
    DEBUG: create skeleton dirs
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/lib/rpm
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/lib/rpm
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/lib/yum
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/lib/yum
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/lib/dbus
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/lib/dbus
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/log
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/log
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/lock/rpm
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/lock/rpm
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/etc/rpm
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/etc/rpm
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/tmp
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/var/tmp
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/var/tmp
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/etc/yum.repos.d
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/etc/yum.repos.d
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/etc/yum
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/etc/yum
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/proc
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/proc
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/sys
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/sys
    DEBUG: touch required files
    DEBUG: touching file: /var/lib/mock/epel-5-x86_64/root/etc/mtab
    DEBUG: touching file: /var/lib/mock/epel-5-x86_64/root/etc/fstab
    DEBUG: touching file: /var/lib/mock/epel-5-x86_64/root/var/log/yum.log
    DEBUG: configure yum
    DEBUG: remove tree: /var/lib/mock/epel-5-x86_64/root/dev
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/dev/pts
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/dev/pts
    DEBUG: ensuring that dir exists: /var/lib/mock/epel-5-x86_64/root/dev/shm
    DEBUG: creating dir: /var/lib/mock/epel-5-x86_64/root/dev/shm
    DEBUG: kver == 2.6.35.13-91.fc14.x86_64
    State Changed: running yum
    DEBUG: mount -n -t proc mock_chroot_proc /var/lib/mock/epel-5-x86_64/root/proc
    DEBUG: Executing command: mount -n -t proc mock_chroot_proc /var/lib/mock/epel-5-x86_64/root/proc
    DEBUG: Child returncode was: 0
    DEBUG: mount -n -t sysfs mock_chroot_sysfs /var/lib/mock/epel-5-x86_64/root/sys
    DEBUG: Executing command: mount -n -t sysfs mock_chroot_sysfs /var/lib/mock/epel-5-x86_64/root/sys
    DEBUG: Child returncode was: 0
    DEBUG: mount -n --bind /var/cache/mock/epel-5-x86_64/yum_cache/ /var/lib/mock/epel-5-x86_64/root/var/cache/yum
    DEBUG: Executing command: mount -n --bind /var/cache/mock/epel-5-x86_64/yum_cache/ /var/lib/mock/epel-5-x86_64/root/var/cache/yum
    DEBUG: Child returncode was: 0
    DEBUG: mount -n --bind /var/cache/mock/epel-5-x86_64/ccache/ /var/lib/mock/epel-5-x86_64/root/tmp/ccache
    DEBUG: Executing command: mount -n --bind /var/cache/mock/epel-5-x86_64/ccache/ /var/lib/mock/epel-5-x86_64/root/tmp/ccache
    DEBUG: Child returncode was: 0
    DEBUG: mount -n --bind /tmp/mock-selinux-pluginqLHpEA /var/lib/mock/epel-5-x86_64/root/proc/filesystems
    DEBUG: Executing command: mount -n --bind /tmp/mock-selinux-pluginqLHpEA /var/lib/mock/epel-5-x86_64/root/proc/filesystems
    DEBUG: Child returncode was: 0
    DEBUG: mount -n -t devpts -o gid=5,mode=0620,ptmxmode=0666,newinstance mock_chroot_devpts /var/lib/mock/epel-5-x86_64/root/dev/pts
    DEBUG: Executing command: mount -n -t devpts -o gid=5,mode=0620,ptmxmode=0666,newinstance mock_chroot_devpts /var/lib/mock/epel-5-x86_64/root/dev/pts
    DEBUG: Child returncode was: 0
    DEBUG: mount -n -t tmpfs mock_chroot_shmfs /var/lib/mock/epel-5-x86_64/root/dev/shm
    DEBUG: Executing command: mount -n -t tmpfs mock_chroot_shmfs /var/lib/mock/epel-5-x86_64/root/dev/shm
    DEBUG: Child returncode was: 0
    DEBUG: /usr/bin/yum --installroot /var/lib/mock/epel-5-x86_64/root/ install buildsys-build
    DEBUG: Executing command: /usr/bin/yum --installroot /var/lib/mock/epel-5-x86_64/root/ install buildsys-build --setopt=tsflags=nocontexts
    DEBUG: http://buildsys.fedoraproject.org/buildgroups/rhel5/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 407 : http://buildsys.fedoraproject.org/buildgroups/rhel5/x86_64/repodata/repomd.xml
    DEBUG: Trying other mirror.
    DEBUG: Error: Cannot retrieve repository metadata (repomd.xml) for repository: groups. Please verify its path and try again
    DEBUG: Child returncode was: 1
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/dev/shm
    DEBUG: Child returncode was: 0
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/dev/pts
    DEBUG: Child returncode was: 0
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/proc/filesystems
    DEBUG: Child returncode was: 0
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/tmp/ccache
    DEBUG: Child returncode was: 0
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/var/cache/yum
    DEBUG: Child returncode was: 0
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/sys
    DEBUG: Child returncode was: 0
    DEBUG: Executing command: umount -n /var/lib/mock/epel-5-x86_64/root/proc
    DEBUG: Child returncode was: 0
    ERROR: Command failed:
    # /usr/bin/yum --installroot /var/lib/mock/epel-5-x86_64/root/ install buildsys-build --setopt=tsflags=nocontexts
    http://buildsys.fedoraproject.org/buildgroups/rhel5/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 407 : http://buildsys.fedoraproject.org/buildgroups/rhel5/x86_64/repodata/repomd.xml
    Trying other mirror.
    Error: Cannot retrieve repository metadata (repomd.xml) for repository: groups. Please verify its path and try again
     
    DEBUG: kill orphans
    [adam@server ~]$ 




Expected results:
yum to install packages inside the chroot env.

Additional info: