v3: fix cron middleware, remove unused code from shared

common/script/fns/nullify.js

@@ -1,5 +1,7 @@
-module.exports = function(user) {
+// TODO remove once v2 is retired
+
+module.exports = function nullify (user) {
   user.ops = null;
   user.fns = null;
-  return user = null;
+  user = null;
 };