staging: lustre: mdc: Make IT_OPEN take lookup bits lock

An earlier commit accidentally changed handling of IT_OPEN,
making it take the MDS_INODELOCK_UPDATE bits lock instead of
MDS_INODELOCK_LOOKUP. This does not cause any known bugs.

Signed-off-by: Patrick Farrell <paf@cray.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8842
Reviewed-on: https://review.whamcloud.com/23797
Fixes: 70a251f68dea ("staging: lustre: obd: decruft md_enqueue() and md_intent_lock()"
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/mdc/mdc_locks.c

@@ -721,7 +721,7 @@ int mdc_enqueue(struct obd_export *exp, struct ldlm_enqueue_info *einfo,
 		LASSERT(!policy);
 
 		saved_flags |= LDLM_FL_HAS_INTENT;
-		if (it->it_op & (IT_OPEN | IT_UNLINK | IT_GETATTR | IT_READDIR))
+		if (it->it_op & (IT_UNLINK | IT_GETATTR | IT_READDIR))
 			policy = &update_policy;
 		else if (it->it_op & IT_LAYOUT)
 			policy = &layout_policy;