build: sync glusterfs.spec.in with Fedora glusterfs.spec

BUG: 819130
Change-Id: I96aeb8fbe8b79bbc058ff9a45167d822abb576ed
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
Reviewed-on: http://review.gluster.org/4877
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>