Creating /var/run/vdsm directory as part of rpm installation

Supervdsm service cannot start without the existence of this directory,
it creates its pid file and socket there. Instead of only set the
directory attributes (%ghost flag) also include the directory as part of the
package.

Change-Id: If615e8c9f0a9031f8b18c768e63491f3e434c01f
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/15170
Reviewed-by: Dan Kenigsberg <danken@redhat.com>