* if the KnowledgeBox have expand_links_content_by_default set to True, don't hide text related to rss links
* add KnowledgeBox PropertySheet to KnowledgeBox portal_type

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@31192 20353a03-c40f-0410-a6d1-a30d3c3de9de