Revert "LU-4403 mds: extra lock during resend lock lookup."

This reverts commit 9ea95abb19c92fae2df52991c1d8d6666ec5f86b.

The above commit was patch set #2 which did not fix the problem.
LU-4403 mds: extra lock during resend lock lookup.

1. If the request does not require open lock, MDT does not
need to search the lock in exp_hash_lock list, because the MDT
will release the lock anyway, and it can always re-enqueue the
request during resend.

2. Lock the resource when the MDS is trying to lookup the lock for
resend request(in mdt_intent_fixup_resent). Otherwise, if the
lock is being released, fixup_resent will return a released lock,
which will cause LBUG when this lock is being released later.

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I3c1aab345fcbb971a85aaa6aac92f22439560ff3