a different portal_type, the Event will migrate to this portal_type during
discoverMetatada process.
Contribution Predicates must focus on filename, content_type and
content_type guessed from data criterions.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@41858 20353a03-c40f-0410-a6d1-a30d3c3de9de