Fixes #7206: Add ability to deploy Katello 2.0

does --version default to nightly?  from the code it doesn't appear to and when running it looks like it tries to install:

http://fedorapeople.org/groups/katello/releases/yum//katello/RHEL/6Server/x86_64/katello-repos-latest.rpm
we should either make --version required or default to nightly.