[PATCH] ocfs2/dlm: Fixes oops in dlm_new_lockres()

Patch fixes a race that can result in an oops while adding a
lockres to the dlm lockres tracking list.

Bug introduced by mainline commit 29576f8b

.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>