"AT->dexterity" migration forgets to migrate "Products.CMFEditions" state attributes

[d-maurer]

The following code from Products.CMFEditions.ArchivistTool.ArchivitTool.prepare states an invariant:

        obj, history_id = dereference(obj, zodb_hook=self)
        if storage.isRegistered(history_id):
            # already registered
            version_id = len(self.queryHistory(obj))
            is_registered = True
        else:
            # object isn't under version control yet
            # A working copy being under version control needs to have
            # a history_id, version_id (starts with 0) and a location_id
            # (the current implementation isn't able yet to handle multiple
            # locations. Nevertheless lets set the location id to a well
            # known default value)
            uidhandler = getToolByName(self, 'portal_historyidhandler')
            history_id = uidhandler.register(obj)
            version_id = obj.version_id = 0
            alsoProvides(obj, IVersioned)
            obj.location_id = 0
            is_registered = False

i.e. if an object is registered, it must have attributes location_id and version_id.

The "AT->dexterity" migration forgets to migrate those attributes. As a consequence, the migrated objects can no longer be edited (--> AttributeError: "location_id").