Add support for GitPython and salt-ssh on FreeBSD masters

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`.

salt/map.jinja

@@ -48,6 +48,8 @@ that differ from whats in defaults.yaml
       'salt_syndic': 'py27-salt',
       'salt_cloud': 'py27-salt',
       'salt_api': 'py27-salt',
+      'salt_ssh': 'py27-salt',
+      'python_git': 'py27-GitPython',
       'config_path': '/usr/local/etc/salt',
       'minion_service': 'salt_minion',
       'master_service': 'salt_master',