to not collide with the recently introduced thread scheduler module.


mysql-test/r/events.result:
  Update test results with new error texts (SCHEDULER -> Event Scheduler,
  grammar).
sql/event_data_objects.cc:
  SCHEDULER -> Event Scheduler.
sql/event_queue.cc:
  SCHEDULER -> Event Scheduler.
sql/event_scheduler.cc:
  SCHEDULER -> Event Scheduler.
sql/events.cc:
  SCHEDULER -> Event Scheduler.
sql/share/errmsg.txt:
  SCHEDULER -> Event Scheduler. Fix English grammar.