LU-3073 test: cancel lru locks for OSC

LU-3073 test: cancel lru locks for OSC

in test_120a of sanity.sh, the locks in LRU of OSC should also be
cancelled for the asynchronous object destroy at MDT could cause
blocking AST sent to client.

Change-Id: Ibb619e2a93f8c70f41f6514149d06a12c4b5aa4e
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: http://review.whamcloud.com/6088
Tested-by: Hudson
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>