Added missing fix from last commit

mysql-test/r/merge-big.result

@@ -7,7 +7,7 @@ drop table if exists t1,t2,t3,t4,t5,t6;
 CREATE TABLE t1 (c1 INT) ENGINE= MyISAM;
 LOCK TABLE t1 WRITE;
 # connection con1
-SET SESSION debug="+d,sleep_open_and_lock_after_open";
+SET GLOBAL debug="+d,sleep_open_and_lock_after_open";
 INSERT INTO t1 VALUES (1);
 # connection default
 # Let INSERT go into thr_multi_lock().
@@ -21,6 +21,6 @@ SELECT * FROM t1;
 c1
 UNLOCK TABLES;
 # connection con1
-SET SESSION debug="-d,sleep_open_and_lock_after_open";
+SET GLOBAL debug="-d,sleep_open_and_lock_after_open";
 # connection default
 DROP TABLE t1;