Small bug fix

ps-modify1 used the user variables @1, @2, @100 set within ps_query and 
           ps_modify. That architecture was wrong, because the dependence
           of ps_modify1 on ps_query and ps_modify makes the test script
           maintenance and the use of these test cases during bug fixing/
           debugging of single sub test cases very uncomfortable.
Therefore these user variables (@1, @2, @100) are also set within ps-modify1.

The result files of the test cases ps_2myisam, ps_3innodb, ps_4heap, ps_6bdb,
ps_7ndb will be affected by that change and show 3 additional lines, but
nothing else will change.

mysql-test/include/ps_modify1.inc

@@ -65,6 +65,9 @@ execute stmt1 using @1000, @duplicate, @5;
 select a,b from t1 where a >= 1000 order by a ;
 delete from t1 where a >= 1000 ;
 
+set @1=1 ;
+set @2=2 ;
+set @100=100 ;
 set @float=1.00;
 set @five='five' ;
 --disable_warnings