IGNORE_INDEX fix for 4.0

mysql-test/r/select.result

@@ -1331,10 +1331,10 @@ table	type	possible_keys	key	key_len	ref	rows	Extra
 t2	ref	fld3	fld3	30	const	1	Using where; Using index
 explain select fld3 from t2 ignore index (fld3) where fld3 = 'honeysuckle';
 table	type	possible_keys	key	key_len	ref	rows	Extra
-t2	index	NULL	fld3	30	NULL	1199	Using where; Using index
+t2	ALL	NULL	NULL	NULL	NULL	1199	Using where
 explain select fld3 from t2 use index (fld1) where fld3 = 'honeysuckle';
 table	type	possible_keys	key	key_len	ref	rows	Extra
-t2	index	NULL	fld3	30	NULL	1199	Using where; Using index
+t2	ALL	NULL	NULL	NULL	NULL	1199	Using where
 explain select fld3 from t2 use index (fld3) where fld3 = 'honeysuckle';
 table	type	possible_keys	key	key_len	ref	rows	Extra
 t2	ref	fld3	fld3	30	const	1	Using where; Using index

sql/sql_base.cc

@@ -1850,6 +1850,7 @@ bool setup_tables(TABLE_LIST *tables)
       for (Field **ptr=table->field ; *ptr ; ptr++)
 	(*ptr)->query_id=0;
     }
+    table->used_keys&= table->keys_in_use_for_query;
   }
   if (tablenr > MAX_TABLES)
   {