fixed clean_location method in appointment form

smash/web/forms/appointment_form.py

@@ -105,6 +105,7 @@ class AppointmentEditForm(AppointmentForm):
         location = self.cleaned_data['location']
         if self.user.locations.filter(id=location.id).count() == 0:
             self.add_error('location', "You cannot create appointment for this location")
+            return None
         else:
             return location