Fix error in having.test to use name instead of number (fixes merge problem)

mysql-test/t/having.test:
  Use error name instead of number

mysql-test/t/having.test

@@ -401,7 +401,7 @@ create table t1(f1 int);
 select f1 from t1 having max(f1)=f1;
 select f1 from t1 group by f1 having max(f1)=f1;
 set session sql_mode='ONLY_FULL_GROUP_BY';
---error 1463
+--error ER_NON_GROUPING_FIELD_USED
 select f1 from t1 having max(f1)=f1;
 select f1 from t1 group by f1 having max(f1)=f1;
 set session sql_mode='';