amount_generator: add backward compatibility for intermediate lines

git-svn-id: https://svn.erp5.org/repos/public/erp5/sandbox/amount_generator@39173 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/mixin/amount_generator.py

@@ -289,6 +289,9 @@ class AmountGeneratorMixin:
             break
         if not quantity:
           continue
+        # Backward compatibility
+        if getattr(aq_base(self), 'create_line', None) == 0:
+          property_dict['resource'] = None
         # Create an Amount object
         amount = newTempAmount(portal,
           # we only want the id to be unique so we pick a random causality