Server starts any binlog dump from Format_description_log_event,
this shifted all offset calculations in mysqlbinlog and made it
to stop the dump earlier than --stop-position. Now mysqlbinlog
takes Format_description_log_event into account


mysql-test/r/mysqlbinlog2.result:
  Bug#27171 mysqlbinlog produces different output depends from option -R
mysql-test/t/mysqlbinlog2.test:
  Bug#27171 mysqlbinlog produces different output depends from option -R