Description of problem:

Some defaults being used internal of mock.py refer to mach-helper:

Near mock.py:595
    config_opts['basedir'] = '/var/lib/mach/roots/' # root name is automatically
added to this
    config_opts['chroot'] = '/usr/sbin/mach-helper chroot'
    config_opts['mount'] = '/usr/sbin/mach-helper mount'
    config_opts['umount'] = '/usr/sbin/mach-helper umount'
    config_opts['rm'] = '/usr/sbin/mach-helper rm'
    config_opts['mknod'] = '/usr/sbin/mach-helper mknod'
    config_opts['yum'] = '/usr/sbin/mach-helper yum'
    config_opts['runuser'] = '/sbin/runuser'

Version-Release number of selected component (if applicable):
mock-0.3-2.fc4

Additional info:
This doesn't have any effects, unless using custom configurations, because the
standard *.cfgs as being shipped with the mock-rpm override these settings.