LU-7549 mdt: cancel the atomic lock in the same thread

LU-7549 mdt: cancel the atomic lock in the same thread

If cross-MDT lock has ATOMIC_CB flag, let's cancel it in
the same thread as blocking_ast(), to make sure the lock
is cancelled completely after unlock().

This will be used when MDT tries to cancel remote locks
during migration (see mdt_lock_objects_in_linkea()).
Only if the remote lock is cancelled completely, then
the next trylock will succeed.

Signed-off-by: Di Wang <di.wang@intel.com>
Change-Id: Ib23eb8eb312252e6eca680d08f8fcd89cf29339c
Reviewed-on: http://review.whamcloud.com/17577
Tested-by: Jenkins
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>