slapos_subscription_request: do not generate discount if the price is 0

master/bt5/slapos_subscription_request/SkinTemplateItem/portal_skins/slapos_subscription_request/SubscriptionRequest_createOpenSaleOrder.py

@@ -122,7 +122,7 @@ open_sale_order.validate()
 #######################################################
 # Discount
 unused_day_count = current_date - start_date
-if 0 < unused_day_count:
+if (subscription_request.getPrice() != 0) and (0 < unused_day_count):
   # If the open order starts before today,
   # generate a discount to the user on his next invoice