Fix the following compile warning:

fs/ocfs2/dlmglue.c:99:30: warning: ‘lockdep_keys’ defined but not used [-Wunused-variable]
 static struct lock_class_key lockdep_keys[OCFS2_NUM_LOCK_TYPES];

Link: http://lkml.kernel.org/r/1536938148-32110-1-git-send-email-zhongjiang@huawei.comSigned-off-by: Nzhong jiang <zhongjiang@huawei.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>