We just need to guess which portal_type must be used with portal_contribution_registry
This patch avoid creating objects on portal_contribution as it's not required.
No need to create and delete object several times.
Thanks to Kazuhiko and Yusei


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@24215 20353a03-c40f-0410-a6d1-a30d3c3de9de