LU-1715 ptlrpc: flock deadlock detection does not work

Flock deadlocks are checked on the first attempt to grant
the flock only. If we try again to grant it after its
blocking lock is cancelled, we don't check for deadlocks
which also may exist.

Perform deadlock detection during reprocess

Xyratex-bug-id: MRP-393
Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com>
Reviewed-by: Vitaly Fertman <vitaly_fertman@xyratex.com>
Reviewed-by: Bruce Korb <bruce_korb@xyratex.com>
Change-Id: Ie4d21da0a0b18458f786c9903663372aa24700fb
Reviewed-on: http://review.whamcloud.com/3553
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>