(PUP-3339) Confine failed test off of Fedora 19
There seems to be a bug in usermod on Fedora 19 which is causing
this acceptance test to fail. The bug does not appear to be present
in Fedora 20. Since Fedora 19 will likely each end of life soon,
just confine the acceptance test off the platform rather than try
to find a work around in puppet.