fixing compilation warning and adding flush logs to test of bug#37313

mysql-test/r/mysqlbinlog.result

@@ -364,6 +364,7 @@ drop table t1;
 shell> mysqlbinlog std_data/corrupt-relay-bin.000624 > var/tmp/bug31793.sql
 set @@global.server_id= 4294967295;
 reset master;
+flush logs;
 select
 (@a:=load_file("MYSQLTEST_VARDIR/tmp/mysqlbinlog_bug37313.binlog"))
 is not null;

mysql-test/t/mysqlbinlog.test

@@ -262,6 +262,7 @@ let $s_id_max=`select (1 << 32) - 1`;
 eval set @@global.server_id= $s_id_max;
 
 reset master;
+flush logs;
 --exec $MYSQL_BINLOG $MYSQLTEST_VARDIR/log/master-bin.000001 > $MYSQLTEST_VARDIR/tmp/mysqlbinlog_bug37313.binlog
 --replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
 eval select

sql/log_event.cc

@@ -976,7 +976,7 @@ void Log_event::print_header(FILE* file, PRINT_EVENT_INFO* print_event_info)
 
   fputc('#', file);
   print_timestamp(file);
-  fprintf(file, " server id %lu  end_log_pos %s ", server_id,
+  fprintf(file, " server id %lu  end_log_pos %s ", (ulong) server_id,
 	  llstr(log_pos,llbuff));
 
   /* mysqlbinlog --hexdump */