main.log_slow failed in buildbot with wrong result

main.log_slow                            w2 [ fail ]

        Test ended at 2017-07-04 13:26:24

CURRENT_TEST: main.log_slow

--- /home/buildbot/build/mysql-test/r/log_slow.result	2017-07-04 06:48:13.000000000 -0400

+++ /home/buildbot/build/mysql-test/r/log_slow.reject	2017-07-04 13:26:24.573246511 -0400

@@ -69,7 +69,7 @@

 0

 select count(*) FROM mysql.slow_log;

 count(*)

-1

+5

 set @@long_query_time=default;

 set global slow_query_log= @org_slow_query_log;

 set @@log_slow_filter=default;

mysqltest: Result content mismatch