Exception handling in getDataStreamList script.

bt5/erp5_wendelin_telecom_ingestion/SkinTemplateItem/portal_skins/erp5_wendelin_telecom/getDataStreamList.py

@@ -5,6 +5,9 @@ data_set = portal_catalog.getResultValue(
            portal_type = "Data Set",
            reference = data_set_reference)
 
+if data_set is None:
+  return []
+
 query_dict = {
   "portal_type": "Data Ingestion Line",
   "resource_portal_type": "Data Product",