Fixed sporadic error in main.backup_locks

The follwoing could happen if InnoDB did some background work while
test was running:

@@ -5,6 +5,8 @@
 SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
 LOCK_MODE      LOCK_TYPE       TABLE_SCHEMA    TABLE_NAME
 MDL_SHARED_HIGH_PRIO   Table metadata lock     test    t1
+MDL_SHARED     Table metadata lock     mysql   innodb_table_stats
+MDL_SHARED     Table metadata lock     mysql   innodb_index_stat

mysql-test/main/backup_locks.result

@@ -2,19 +2,19 @@
 # Test lock taken
 #
 BACKUP LOCK test.t1;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 LOCK_MODE	LOCK_TYPE	TABLE_SCHEMA	TABLE_NAME
 MDL_SHARED_HIGH_PRIO	Table metadata lock	test	t1
 BACKUP UNLOCK;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 LOCK_MODE	LOCK_TYPE	TABLE_SCHEMA	TABLE_NAME
 BACKUP LOCK t1;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 LOCK_MODE	LOCK_TYPE	TABLE_SCHEMA	TABLE_NAME
 MDL_SHARED_HIGH_PRIO	Table metadata lock	test	t1
 BACKUP UNLOCK;
 BACKUP LOCK non_existing.t1;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 LOCK_MODE	LOCK_TYPE	TABLE_SCHEMA	TABLE_NAME
 MDL_SHARED_HIGH_PRIO	Table metadata lock	non_existing	t1
 BACKUP UNLOCK;

mysql-test/main/backup_locks.test

@@ -11,14 +11,14 @@
 --echo #
 
 BACKUP LOCK test.t1;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 BACKUP UNLOCK;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 BACKUP LOCK t1;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 BACKUP UNLOCK;
 BACKUP LOCK non_existing.t1;
-SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info;
+SELECT LOCK_MODE, LOCK_TYPE, TABLE_SCHEMA, TABLE_NAME FROM information_schema.metadata_lock_info where table_name not like "innodb_%";
 BACKUP UNLOCK;
 
 --echo #