Homebrew's tap directory naming has changed

It's now Library/Taps/${user}/homebrew-${repo}
Require homebrew with new taps directory convention

For 1db7ffa
Merge pull request #46 from boxen/use-new-tap-directory

Support new tap directory naming convention
Ensure the parent tap directory exists too
Merge branch 'master' of github.com:boxen/puppet-homebrew