Rename osfamily ot osvariant for compatibility with new facter

The new version of facter only permits default facts to be overridden
using environmental variables.  Use new fact called osvariant to
identify CernVM.  Replace all occurences of osfamily with osvariant
except packagerepos/manifests/init.pp where osfamily was intended.
Add logic for message concerning CernVM.

Changes:
	modified:   apf/manifests/init.pp
	modified:   autofs/manifests/init.pp
	modified:   cernvm/manifests/init.pp
	modified:   condor/manifests/client.pp
	modified:   condor/manifests/init.pp
	modified:   cvmfs/manifests/init.pp
	renamed:    gce_node/lib/facter/osfamily.rb -> gce_node/lib/facter/osvariant.rb
	modified:   gce_node/manifests/init.pp
	modified:   gce_node/manifests/packages.pp
	modified:   packagerepos/manifests/init.pp
	modified:   xrootd/manifests/init.pp