21868/stable/cherry pick mavericks pkging

This PR includes the cherry-picking of four commits from facter/master into
facter/stable: bdd793a, ff44c59, db8411c, and c3c6f6d. These commits in
aggregate update facter Mac packaging to be compatible with OSX Mavericks by
default, by moving the packages into a ruby load path compatible with
Mavericks, /Library/Ruby/Site. This should be backwards compatible with all
supported OSX versions, as this path is in the ruby load path by default on all
of them. Commits to this effect have been released in both Puppet (3.4) and
Hiera (1.3) but not yet in facter.