fixed error message numbers in union test

mysql-test/t/union.test:
  fixed error message numbers

mysql-test/t/union.test

@@ -19,11 +19,11 @@ select 't1',b,count(*) from t1 group by b UNION select 't2',b,count(*) from t2 g
 explain select a,b from t1 union all select a,b from t2;
 
 # Test some error conditions with UNION
---error 1213
+--error 1214
 select a,b from t1 into outfile 'skr' union select a,b from t2;
---error 1213
-select a,b from t1 order by a union select a,b from t2;
 --error 1214
+select a,b from t1 order by a union select a,b from t2;
+--error 1215
 select a,b from t1 union select a from t2;
 
 drop table t1,t2;