mod_storage_xmlarchive: Fix "user" iteration API Fixes use in prosody-migrator. Otherwise this particular API is not used much, or this would have been noticed before. Usually it is a different store like 'accounts' that is responsible for providing the authoritative list of users. Thanks Ge0rG for testing

module:hook("authentication-success", function (event)
	local session = event.session;
	local sasl_handler = session.sasl_handler;
	session.log("info", "Authenticated with %s", sasl_handler and sasl_handler.selected or "legacy auth");
end);