fixed: photo_set.count() raises a Exception when a new Event will be added.

src/events/models.py

@@ -165,7 +165,7 @@ class Event(models.Model):
             self.location = master_event.location
             self.url = master_event.url
             self.image = self.image or master_event.image
-        self.photo_count = self.photo_set.count()
+        self.photo_count = self.photo_set.count() if self.pk else 0
         super(Event, self).save(**kwargs)
 
         # Update the Hanchans if necessary: