from filesystem to ZODB, unwrap the created object before adding it to
the PersistentMapping, failing to do so resulted in "Can't Pickle
objects in acquisition wrappers" when serializing the object


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@43155 20353a03-c40f-0410-a6d1-a30d3c3de9de