Install python3 in Fedora or RedHat > 7

Fedora repo [1] has python3 packages, start consuming those.

[1] http://trunk.rdoproject.org/fedora/puppet-passed-ci/

Change-Id: I7dd423e8b15f0d8b98f365ef0562d716068eb3aa

manifests/params.pp

@@ -3,7 +3,8 @@
 class glare::params {
   include ::openstacklib::defaults
 
-  if ($::os_package_type == 'debian') {
+  if ($::os_package_type == 'debian') or ($::os['name'] == 'Fedora') or
+    ($::os['family'] == 'RedHat' and Integer.new($::os['release']['major']) > 7) {
     $pyvers = '3'
   } else {
     $pyvers = ''