object-storage: Store the lock file in /var/run/swift.

* Openstack swift uses the /var/run/swift directory to store the pid files
  for all the servers.

* Also, added a script that would unmount the gluster client on a volume stop.

Change-Id: Ib5b9a2964987ca7696d9a2570f1f7af8490b2168
BUG: 861497
Signed-off-by: Mohammed Junaid <junaid@redhat.com>
Reviewed-on: http://review.gluster.org/4417
Reviewed-by: Peter Portante <pportant@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>