do not allow locks on undefined

lib/utils.js

@@ -7,6 +7,8 @@ var Utils = {};
 Utils.runLocked = function(token, cb, task) {
   var self = this;
 
+  $.shouldBeDefined(token);
+
   Lock.get(token, function(lock) {
     var _cb = function() {
       cb.apply(null, arguments);