branches/zip: innodb.test: Use ER_DROP_INDEX_FK instead of a numeric

error code.  Apparently, the numeric error codes in MySQL 5.1 are changing.

mysql-test/innodb.result

@@ -1515,7 +1515,7 @@ t2	CREATE TABLE `t2` (
 ) ENGINE=InnoDB DEFAULT CHARSET=latin1
 drop index id2 on t2;
 drop index id on t2;
-Got one of the listed errors
+ERROR HY000: Cannot drop index 'id': needed in a foreign key constraint
 show create table t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (

mysql-test/innodb.test

@@ -1095,7 +1095,7 @@ show create table t2;
 create index id2 on t2 (id);
 show create table t2;
 drop index id2 on t2;
---error 1542,1542
+--error ER_DROP_INDEX_FK
 drop index id on t2;
 show create table t2;
 drop table t2;