redhat/packages: set allow_virtual to True

RDO packaging provides virtual packages. Puppet 3 is setting
allow_virtual to False and in 4 it's set to True.
Force it to True to avoid issues when deploying RDO.

Change-Id: I54ade4cb4add005429840eb7d8970d736b1a0b22

manifests/init.pp

@@ -6,5 +6,10 @@ class openstack_integration {
     package { 'openstack-selinux':
         ensure => 'latest'
     }
+    # Some packages provided by RDO are virtual
+    # allow_virtual is false in Puppet 3 and will be true
+    # in Puppet 4. So let's set it to True.
+    # We still support Puppet 3 until distros ship Puppet 4 by default.
+    Package<| tag == 'openstack' |> { allow_virtual => true }
   }
 }