configure business_process only if exists (not exist in legacy test).

product/ERP5/tests/testAdvancedInvoicing.py

@@ -398,7 +398,9 @@ class TestAdvancedSaleInvoice(TestAdvancedInvoice):
   def afterSetUp(self):
     super(TestAdvancedSaleInvoice, self).afterSetUp()
     # register builders for advanced invoicing.
-    business_process = self.portal.business_process_module.erp5_default_business_process
+    business_process = self.portal.unrestrictedTraverse(
+      'business_process_module/erp5_default_business_process', None)
+    if business_process is not None:
       business_process.invoice.setDeliveryBuilderList([
           'portal_deliveries/advanced_purchase_invoice_builder',
           'portal_deliveries/advanced_sale_invoice_builder',