This change tweaks the GitPython package installation state to support
alternate package names (on FreeBSD, it's called "py27-GitPython").
Also, on FreeBSD salt-ssh is included in the "py27-salt" package by
default, requiring an update to `distro_map`.
* Install pygit from package
* Add Official Salt ZeroMQ 4 COPR repository
Note that Salt itself is assumed to already to be available to the system via yum, via EPEL for example