[migration] fix handling of default value for boolean attributes
We can't assert that the old value is 'True' or 'False', because False
used to be stored as an empty string in pre-3.18 versions.
.. -*- coding: utf-8 -*-
Dernières modifications
-----------------------
* la table des `derniers changements`_ fournit un exemple d'utilisation de RQL
pour récupérer les derniers changements ayant eu lieu sur ce site.
.. _`derniers changements`: view?rql=Any+M%2CX+WHERE+X+modification_date+M+ORDERBY+M+DESC+LIMIT+30