sys_vars.slow_query_log_func failed in buildbot, results mismatch

sys_vars.slow_query_log_func             w1 [ fail ]

        Test ended at 2017-11-03 01:27:55

CURRENT_TEST: sys_vars.slow_query_log_func

--- /usr/local/mariadb-10.2.11-linux-i686/mysql-test/suite/sys_vars/r/slow_query_log_func.result	2017-11-03 00:29:20.000000000 +0100

+++ /usr/local/mariadb-10.2.11-linux-i686/mysql-test/suite/sys_vars/r/slow_query_log_func.reject	2017-11-03 01:27:55.000000000 +0100

@@ -85,7 +85,7 @@

 SELECT t1.c1-self.c1 > 1 FROM t1, t1 as self WHERE t1.c0=self.c0+1 ORDER BY t1.c0;

 t1.c1-self.c1 > 1

 1

-1

+0

 1

 DROP TRIGGER tf_before;

 DROP FUNCTION f_slow_now;

mysqltest: Result content mismatch