slapos_accounting: do not invalidate open order, as it breaks the simulation

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

@@ -95,7 +95,7 @@ if open_sale_order.getValidationState() == 'validated':
           assert instance_tree.getCausalityState() == 'diverged'
           instance_tree.converge(comment="Last open order: %s" % open_order_line.getRelativeUrl())
 
-          open_sale_order.invalidate()
+          open_sale_order.archive()
           storeWorkflowComment(open_sale_order, "Instance Tree destroyed: %s" % instance_tree.getRelativeUrl())
         elif (instance_tree.getCausalityState() == 'diverged'):
           instance_tree.converge(comment="Nothing to do on open order.")