Fixed test case rpl_incident.test (synchronize drop table, masked IO thread behaviour)


mysql-test/r/rpl_incident.result:
  Masking master_log_file since IO thread is not synchronized in rpl_incident.test
mysql-test/t/rpl_incident.test:
  Masking master_log_file since IO thread is not synchronized in rpl_incident.test
  Correcting drop of table so it is synchronized
sql/log_event.cc:
  Added extra parenthesis to remove compiler warning