#20129 Handling for expirationdate set to None on some objects

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs/Naaya@20955 a0171fae-0946-0410-966d-b1775066cd26
released 3.3.56, new version 3.3.57

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs/Naaya@20956 a0171fae-0946-0410-966d-b1775066cd26