LU-2683 lov: release all locks in closure to release sublock

LU-2683 lov: release all locks in closure to release sublock

We used to only release current parent lock, this may cause deadlock
if the sublock is shared. See stacktrace of LU-2683 and LU-874 for
details.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: Ibe5fc364ef22a279f23bb24ad1311a1ad09be369
Reviewed-on: http://review.whamcloud.com/5208
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Prakash Surya <surya1@llnl.gov>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>