SUScheduledUpdateDriver doesn't call updaterDidNotFindUpdate

When the update i started using [updater checkForUpdatesInBackground], the clients [delegate didFindValidUpdate] is called (when an update is available) but [delegate updaterDidNotFindUpdate] is not.

This is because [SUScheduledUpdateDriver didFindValidUpdate] calls [super didFindValidUpdate] but [.. didNotFindUpdate] does not.

The fix is to manually call the delegate at the top of didNotFindUpdate.

Current code:
- (void)didNotFindUpdate
{
 [self abortUpdate]; // Don't tell the user that no update was found; this was a scheduled update.
}

Fixed code:
- (void)didNotFindUpdate
{
 if ([[updater delegate] respondsToSelector:@selector(updaterDidNotFindUpdate:)])
  [[updater delegate] updaterDidNotFindUpdate:updater];
 [self abortUpdate]; // Don't tell the user that no update was found; this was a scheduled update.
}