instead of current --old-log-format and
--both-log-formats options


mysql-test/mysql-test-run.pl:
  use new option instead of the old one for testing
mysql-test/r/im_utils.result:
  correct result file
sql/log.cc:
  use log event handler flags instead of enum_printer
sql/log.h:
  Add log event handler flags to simplify log
  option processing