partially cherry-pick from mysql/5.6.
No test case (mysql/5.6 test case is useless, the correct
test case uses too much memory)

commit e061985813db54948f99892d89f7e076242473a5
Author:  <Dao-Gang.Qu@sun.com>
Date:   Tue Jun 1 15:02:22 2010 +0800

    Bug #49931          Incorrect type in read_log_event error
    Bug #49932          mysqlbinlog max_allowed_packet hard coded to 1GB