ocfs2: unlock rw lock if inode lock failed

In ocfs2_file_aio_write(), it does ocfs2_rw_lock() first and then
ocfs2_inode_lock().

But if ocfs2_inode_lock() failed, it goes to out_sems without unlocking
rw lock.  This will cause a bug in ocfs2_lock_res_free() when testing
res->l_ex_holders, which is increased in __ocfs2_cluster_lock() and
decreased in __ocfs2_cluster_unlock().

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: "Duyongfeng (B)" <du.duyongfeng@huawei.com>
Acked-by: Sunil Mushran <sunil.mushran@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>