Changed the behaviour of the --event-scheduler option when used without an arguments. It
now turns the option on.


mysql-test/r/events_bugs.result:
  Test that --event-scheduler with no options in events_bugs-master.opt turns the option
  on.
mysql-test/t/events_bugs.test:
  Test that --event-scheduler with no options in events_bugs-master.opt turns the option
  on.
sql/events.cc:
  Changed the behaviour of the --event-scheduler option when used without an arguments.
  It now turns the option on.
mysql-test/t/events_bugs-master.opt:
  Test that --event-scheduler with no options in events_bugs-master.opt turns the option
  on.