If we decide in the security script that we don't want to update the
assigned roles for this object, we can just have it return None instead of
a dict or list of dicts.

This may happen for example when a site manager creates a new object.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@3837 20353a03-c40f-0410-a6d1-a30d3c3de9de