slapos_accounting: do not hardcode any reversal trick

Invoice must be correctly grouped.

master/bt5/slapos_accounting/SkinTemplateItem/portal_skins/slapos_accounting/AccountingTransaction_getPaymentState.py

@@ -30,14 +30,7 @@ else:
         paid = False
         break
 
-  reversal = portal.portal_catalog.getResultValue(
-      portal_type="Sale Invoice Transaction",
-      simulation_state="stopped",
-      default_causality_uid=context.getUid()
-    )
-  if reversal is not None and (context.getTotalPrice() + reversal.getTotalPrice()) == 0:
-    result = "Cancelled"
-  elif paid:
+  if paid:
     result = "Paid"
   elif context.getTotalPrice() == 0:
     result = "Free!"