Trivial cleanups and whitespace change in Event Scheduler code.

A larger patch is to come, this is to exclude rudimentary changes
from it.


sql/event_data_objects.cc:
  Whitespace change.
sql/event_data_objects.h:
  Remove debug allocators - we have safemalloc.
sql/event_db_repository.cc:
  Whitespace change.
sql/event_db_repository.h:
  Whitespace change.
sql/event_queue.cc:
  Remove an unused structure. Whitespace change.
sql/event_queue.h:
  Whitespace.
sql/event_scheduler.cc:
  Whitespace change.
sql/event_scheduler.h:
  Add comments. Whitespace change.
sql/events.cc:
  Whitespace change.
sql/events.h:
  Trivial cleanups.

sql/event_queue.h

@@ -34,7 +34,7 @@ public:
 
   bool
   init_queue(THD *thd);
-  
+
   void
   deinit_queue();