Cut 7 (refactoring)

db_repository is no more embedded in the Events
singleton. Therefore a change to Events_db_repository
won't mean recompile of all files in the server which include events.h


sql/event_data_objects.cc:
  db_repository is no more embedded in the Events
  singleton. Therefore a change to Events_db_repository
  won't mean recompile of all files in the server which include events.h
sql/event_db_repository.cc:
  db_repository is no more embedded in the Events
  singleton. Therefore a change to Events_db_repository
  won't mean recompile of all files in the server which include events.h
sql/events.cc:
  db_repository is no more embedded in the Events
  singleton. Therefore a change to Events_db_repository
  won't mean recompile of all files in the server which include events.h
sql/events.h:
  db_repository is no more embedded in the Events
  singleton. Therefore a change to Events_db_repository
  won't mean recompile of all files in the server which include events.h
sql/mysqld.cc:
  db_repository is no more embedded in the Events
  singleton. Therefore a change to Events_db_repository
  won't mean recompile of all files in the server which include events.h