build: glusterfs.spec.in, minor/nit changes to sync with Fedora spec

minor/nit changes to sync with Fedora spec

Change-Id: I939eb79d5c3a19c09a3df3f30c82c86e1a610cd0
BUG: 1091408
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
Reviewed-on: http://review.gluster.org/7565
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>