cleanup before throwin away DYNAMIC_ARRAY for event storage,
once reallocated I get dangling pointers so that's not good.
solution will be found however ;)


sql/event.cc:
  - remove unneeded variables
  - remove commented out code
  - remove non-cs compliant comment
  - fix a bug when removing from memory cache
  - better close the tables than relying on sql_parse.cc::do_command()
    to do that
sql/event_executor.cc:
  - cleanup
sql/event_priv.h:
  -cleanup
sql/event_timed.cc:
  cleanup