Fix for bug 254 : the first Start_log_event after server startup will
have created=now(), whereas the next ones (FLUSH LOGS, auto rotation)
will have created=0. Before this, it was always now().
This way, slaves >=4.0.14 will know when they must
drop stale temp tables or not. The next task is now modify 4.0.14 to
implement this.


sql/log.cc:
  Fix for bug 254 : the first Start_log_event after server startup will
  have created=now(), whereas the next ones (FLUSH LOGS, auto rotation)
  will have created=0. Before this, it was always now().
  This way, slaves >=4.0.14 will know when they must
  drop stale temp tables or not.
sql/log_event.h:
  An explanation.
sql/sql_class.h:
  Prototype change (see log.cc).