Description of problem:
Run a virt-install command with both parameters '--nonetworks' and '--bridge', such as:
# virt-install -n demo -r 1024 --disk path=/var/lib/libvirt/images/demo.img,size=6 --nonetworks --bridge=breth0sd -c /dev/cdrom
ERROR    Cannot use --bridges with --nonetworks

There is a typo of above error message, the '--bridges' should be changed to '--bridge'.
As '--bridges' was not valid parameters in virt-install. If you use '--bridges' in virt-install command, error message should pop up as:
"virt-install: error: no such option: --bridges"


Version-Release number of selected component (if applicable):
python-virtinst-0.600.0-8.el6.noarch

How reproducible:
100%

Steps to Reproduce:
Run a virt-install command with both parameters '--nonetworks' and '--bridge', such as:
# virt-install -n demo -r 1024 --disk path=/var/lib/libvirt/images/demo.img,size=6 --nonetworks --bridge=breth0sd -c /dev/cdrom
check the error message

Actual results:
ERROR    Cannot use --bridges with --nonetworks

Expect result:
ERROR    Cannot use --bridge with --nonetworks