action_list is not None

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@5358 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/BusinessTemplate.py

@@ -4147,7 +4147,7 @@ Business Template is a set of definitions, such as skins, portal types and categ
       bt_hidden_content_type_list = []
       bt_property_sheet_list = []
       bt_base_category_list = []
-      bt_action_list = getattr(self, 'template_action_path', [])  
+      bt_action_list = getattr(self, 'template_action_path', []) or []
       bt_action_list = list(bt_action_list)
       bt_portal_types_id_list = list(self.getTemplatePortalTypeIdList())      
       p = self.getPortalObject()