PUP-3255 improve acceptance pre suite

fix git install options
fix redhat json install issues
fix git url#branch generation

helps get machines up quickly when manual testing or writing tests.
might impact CI?
@er0ck so the Rakefile also does similar pre-processing, and I don't think we should duplicate it here.  You are running a manual beaker run drawing in the git/options.rb (which are not complete -- they are merged by the Rakefile again), but regardless, that's relying on shorthand for the repos (if no pre-processing is done before reaching Beaker).  I think the actual bug here is that Beaker is expecting PUPPET, HIERA, FACTER, and git/options.rb is lower-case. https://github.com/puppetlabs/beaker/blob/master/lib/beaker/options/parser.rb#L105-L120  So I think what we need is to change config/git/options.rb's :install array to be ['FACTER#stable', etc.]