btrfs: btrfs_relocate_chunk pass extent_root to btrfs_end_transaction

In btrfs_relocate_chunk, we get a transaction handle via
btrfs_start_trans_remove_block_group, which starts the transaction
using the extent root.  When we call btrfs_end_transaction, we're calling
it using the chunk root.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -2941,7 +2941,7 @@ static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
 	 * chunk tree entries
 	 */
 	ret = btrfs_remove_chunk(trans, root, chunk_offset);
-	btrfs_end_transaction(trans, root);
+	btrfs_end_transaction(trans, extent_root);
 	return ret;
 }