Btrfs: BUG_ON is deleted from the caller of btrfs_truncate_item & btrfs_extend_item

Currently, btrfs_truncate_item and btrfs_extend_item returns only 0.
So, the check by BUG_ON in the caller is unnecessary.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/dir-item.c

@@ -50,7 +50,6 @@ static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
 		if (di)
 			return ERR_PTR(-EEXIST);
 		ret = btrfs_extend_item(trans, root, path, data_size);
-		WARN_ON(ret > 0);
 	}
 	if (ret < 0)
 		return ERR_PTR(ret);