This fixes several unit tests (with not executable activities) where an object
is created and deleted in the same transaction, whereas an interaction
(ex: document_security_interaction_workflow) creates activities for this object
just before committing. The 'flush' happens earlier.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@42281 20353a03-c40f-0410-a6d1-a30d3c3de9de