Btrfs: update inode ctime when using links

Currently we fail xfstest 236 because we're not updating the inode ctime on
link. This is a simple fix, and makes it so we pass 236 now.

Signed-off-by: Josef Bacik <[e-mail]>
Signed-off-by: Chris Mason <[e-mail]>

fs/btrfs/inode.c

···
 		return -EPERM;
 
 	btrfs_inc_nlink(inode);
+	inode->i_ctime = CURRENT_TIME;
 
 	err = btrfs_set_inode_index(dir, &index);
 	if (err)