Lock init script when vdsmd starts up until the service is stopped

As described in:
http://fedoraproject.org/wiki/Packaging:SysVInitScript#Why_do_SysV_initscripts_with_resident_daemons_require_lock_files.3F
This patch adds lock mechanism between stop and start operations.

Change-Id: I7bf346946179e5bb2a91ab33d6b917f280a90a57
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=984616
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/17662
Reviewed-by: Dan Kenigsberg <danken@redhat.com>