slapos_accounting: do not expand packing list if no invoice is supposed to be generated

(aka, no need for slapos_consumption_trade_condition)

master/bt5/slapos_accounting/SkinTemplateItem/portal_skins/slapos_simulation/PackingList_getRuleReference.py

-if context.getPortalType() == 'Sale Packing List' \
-  and context.getSpecialise() == 'sale_trade_condition_module/slapos_consumption_trade_condition':
-  # no rule for consumption
+# Do need to generate invoices in case no section are defined
+source_section = context.getSourceSection()
+destination_section = context.getDestinationSection()
+if source_section == destination_section or source_section is None \
+    or destination_section is None:
   return None
+
 return 'default_delivery_rule'