f2fs: fix omitting to update inode page

The f2fs_set_link updates its parent inode number, so we should sync this to
the inode block.
Otherwise, the data can be lost after sudden-power-off.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/namei.c

@@ -447,6 +447,7 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		else
 			release_orphan_inode(sbi);
 
+		update_inode_page(old_inode);
 		update_inode_page(new_inode);
 	} else {
 		err = f2fs_add_link(new_dentry, old_inode);