Fix sporadic failure in test rpl.rpl_rotate_logs

The test started failing after push of MDEV-31404.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

mysql-test/suite/rpl/r/rpl_rotate_logs.result

@@ -70,8 +70,6 @@ master-bin.000002	#
 master-bin.000003	#
 SELECT @time_for_purge:=DATE_ADD('tmpval', INTERVAL 1 SECOND);
 purge master logs before (@time_for_purge);
-Warnings:
-Note	1375	Binary log 'master-bin.000003' is not purged because it is the current active binlog
 show binary logs;
 Log_name	File_size
 master-bin.000003	#

mysql-test/suite/rpl/t/rpl_rotate_logs.test

@@ -134,7 +134,12 @@ remove_file $MYSQLTEST_VARDIR/tmp/rpl_rotate_logs.tmp;
 --eval SELECT @time_for_purge:=DATE_ADD('$tmpval', INTERVAL 1 SECOND)
 --enable_result_log
 
+# Disable the warning "is not purged because it is the current active binlog".
+# (If the purge is delayed, this warning will not occur, causing .result
+# difference).
+--disable_warnings
 purge master logs before (@time_for_purge);
+--enable_warnings
 source include/show_binary_logs.inc;
 insert into t2 values (65);
 sync_slave_with_master;