spec: enable gluster upstream and on fedora 19

The gluster package should be always enabled upstream or since fedora 19
in koji builds.

Change-Id: I68436bf10cecdaea8b3ce6c95797aac4895ec482
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/13791
Reviewed-by: Dan Kenigsberg <danken@redhat.com>