Description of problem:
Creating custom Live CD with -b option does not work

Version-Release number of selected component:
livecd-tools-18.11-1.fc18

Additional info:
libreport version: 2.0.12
abrt_version:   2.0.11
cmdline:        /usr/bin/python -tt /bin/livecd-creator -t /mnt/var/tmp -c /home/naresh/livecd-F18-Custom.ks -f F18-CUSTOM -b F18-CUSTOMv1.iso --cache=/mnt/var/tmp
kernel:         3.6.0-0.rc6.git0.2.fc18.x86_64

backtrace:
:creator.py:527:mount:OSError: [Errno 17] File exists
:
:Traceback (most recent call last):
:  File "/bin/livecd-creator", line 226, in <module>
:    sys.exit(main())
:  File "/bin/livecd-creator", line 208, in main
:    creator.mount(options.base_on, options.cachedir)
:  File "/usr/lib/python2.7/site-packages/imgcreate/creator.py", line 527, in mount
:    os.symlink("/proc/self/mounts", self._instroot + "/etc/mtab")
:OSError: [Errno 17] File exists
:
:Local variables in innermost frame:
:cachesrc: '/mnt/var/tmp'
:d: '/proc'
:f: '/mnt/var/tmp'
:dest: '/var/cache/yum'
:base_on: 'F18-CUSTOMv1.iso'
:cachedir: '/mnt/var/tmp'
:self: <imgcreate.live.x86LiveImageCreator object at 0x20c23d0>