r12242: - make the push notifications triggered by the change count

r12242: - make the push notifications triggered by the change count
- for now we fake the change count to '1', so we'll still have periodicly triggered push
  notifies, the interval is the 'wreplsrv:periodic_interval=60'
- add the 'pushUseInform' attribute to the wreplPartner objectClass
  to configure if we'll use WREPL_REPL_INFORM notifies

metze