return empty list instead of none when no property defined on portal type roles

remove trailling spaces


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@8391 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/BusinessTemplate.py

@@ -2005,7 +2005,7 @@ class PortalTypeRolesTemplateItem(BaseTemplateItem):
               (property, prop_value)
       # multi
       for property in ('category', 'base_category'):
-        for prop_value in role.get(property):
+        for prop_value in role.get(property, []):
           xml_data += os.linesep+"   <multi_property "\
           "id='%s'>%s</multi_property>" % (property, prop_value)
       xml_data += os.linesep+"  </role>"