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
Patch-Set: 1