f2fs: do not set LOST_PINO for renamed dir

After renaming a directory, fsck could detect unmatched pino. The scenario
can be reproduced as the following:

	$ mkdir /bar/subbar /foo
	$ rename /bar/subbar /foo

Then fsck will report:
[ASSERT] (__chk_dots_dentries:1182)  --> Bad inode number[0x3] for '..', parent parent ino is [0x4]

Rename sets LOST_PINO for old_inode. However, the flag cannot be cleared,
since dir is written back with CP. So, let's get rid of LOST_PINO for a
renamed dir and fix the pino directly at the end of rename.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>