Bug#23631 "Events: SHOW VARIABLES doesn't work when mysql.event 
is damaged:


mysql-test/r/events.result:
  Update results (a post-merge fix)
mysql-test/r/events_bugs.result:
  Update results (a post-merge fix)
mysql-test/r/events_scheduling.result:
  Update results (a post-merge fix)
mysql-test/t/events_scheduling.test:
  Make sure this test has no races.
sql/event_data_objects.cc:
  Manual post-merge fix for the events replication patch.
sql/event_data_objects.h:
  A post-merge fix.
sql/event_db_repository.cc:
  A post-merge fix.
sql/event_scheduler.cc:
  We should drop the event inside ::execute since there we have
  the right credentials to do so (otherwise Events::drop_event
  returns "access denied" error).
sql/events.cc:
  A post-review fix for: rename start_or_stop_event_scheduler
  to switch_event_scheduler_state.
sql/events.h:
  A post-review fix for: rename start_or_stop_event_scheduler
  to switch_event_scheduler_state.
sql/set_var.cc:
  A post-review fix for: rename start_or_stop_event_scheduler
  to switch_event_scheduler_state.
sql/sql_yacc.yy:
  Remove unused declaratoins.