ext4: correct error label in ext4_rename()

The backport of upstream patch 5dccdc5a ("ext4: do not iput inode
under running transaction in ext4_rename()") introduced a regression on
the stable kernels 4.14 and older. One of the end_rename error label was
forgetting to change to release_bh, which may trigger below bug.

 ------------[ cut here ]------------
 kernel BUG at /home/zhangyi/hulk-4.4/fs/ext4/ext4_jbd2.c:30!
 ...
 Call Trace:
  [<ffffffff8b4207b2>] ext4_rename+0x9e2/0x10c0
  [<ffffffff8b331324>] ? unlazy_walk+0x124/0x2a0
  [<ffffffff8b420eb5>] ext4_rename2+0x25/0x60
  [<ffffffff8b335104>] vfs_rename+0x3a4/0xed0
  [<ffffffff8b33a7ad>] SYSC_renameat2+0x57d/0x7f0
  [<ffffffff8b33c119>] SyS_renameat+0x19/0x30
  [<ffffffff8bc57bb8>] entry_SYSCALL_64_fastpath+0x18/0x78
 ...
 ---[ end trace 75346ce7c76b9f06 ]---

Fixes: 2fc8ce56 ("ext4: do not iput inode under running transaction in ext4_rename()")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: Id0bdb1f42110b65df6d6f4f948e7eaec035fef12