ocfs2: flock: drop cross-node lock when failed locally

ocfs2_do_flock() calls ocfs2_file_lock() to get the cross-node clock and
then call flock_lock_file_wait() to compete with local processes.  In
case flock_lock_file_wait() failed, say -ENOMEM, clean up work is not
done.  This patch adds the cleanup --drop the cross-node lock which was
just granted.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>