rpm: fix broken glusterfs-server install of hooks

the %ghost hook directories are no longer ghosts now that files
are installed in them

Change-Id: I6133b891c73d87e4e35dc9c6c7ba7febbc9e2e7f
BUG: 1080970
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
Reviewed-on: http://review.gluster.org/7391
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Reviewed-by: Justin Clift <justin@gluster.org>
Tested-by: Justin Clift <justin@gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>