galera.galera_suspend_slave failed in buildbot with wrong error code

galera.galera_suspend_slave 'xtradb'     w2 [ fail ]

        Test ended at 2017-09-07 06:57:56

CURRENT_TEST: galera.galera_suspend_slave

mysqltest: At line 33: query 'INSERT INTO t1 VALUES (1)' succeeded - should have failed with errno 1047...

The result from queries just before the failure was:

CREATE TABLE t1 (f1 INTEGER PRIMARY KEY) ENGINE=InnoDB;

Suspending node_2 ...

INSERT INTO t1 VALUES (1);

 - saving '/dev/shm/var/2/log/galera.galera_suspend_slave-xtradb/' to '/dev/shm/var/log/galera.galera_suspend_slave-xtradb/'