ocfs2: fix deadlock risk when kmalloc failed in dlm_query_region_handler

ocfs2: fix deadlock risk when kmalloc failed in dlm_query_region_handler

In dlm_query_region_handler(), once kmalloc failed, it will unlock
dlm_domain_lock without lock first, then deadlock happens.

Signed-off-by: Zhonghua Guo <guozhonghua@h3c.com>
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Tested-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>