Btrfs: remove extra run_delayed_refs in update_cowonly_root

This got added with my dirty_bgs patch, it's not needed.  Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/transaction.c

@@ -1052,9 +1052,6 @@ static int update_cowonly_root(struct btrfs_trans_handle *trans,
 		ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
 		if (ret)
 			return ret;
-		ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
-		if (ret)
-			return ret;
 	}
 
 	return 0;