Use the old homebrew recipe version

Some machines can have a old version of homebrew since boxen doesn't
update homebrew automatically.
Add system puppet manifest for gitconfig.

For all of our Mac systems it is necessary to have a proxy to get out to
the Internet. We're going to need the capability to override this.
Fix the spec to pass.

My copy and paste blunder.
Fixing git::config::system problems.

@Dishwasha helped me out here. There's a lot of testing that he's been
doing for our corporate network needs. For the most part it was a bunch
of copy and paste blunders.
Merge pull request #22 from johnbellone/feature/gitconfig-global

Add system puppet manifest for gitconfig.