[server/test] Turn "pull" method of LDAPFeedTestBase into a staticmethod Because it does not use reference to "self" (which should be "cls" for classmethod).

[py3] Use six.text_type instead of unicode in _CWSourceCfgMixIn.update_config()

[server] Drop condition on "3.10" migration in repo.init_sources_from_database() We'll duplicate the code of this method in forthcoming changeset so clean it up a bit of old stuff.