title: $resource success callback returning $promise
body: <p>Using Angular 1.2.14, $resource's success callback should return an object, but it sometimes gets a $promise. The node/express web service is returning null, but Angular interprets it as a $promise. When a non-null is returned from the web service, the success callback gets the object as expected. </p>
  
  <pre><code>$resource('/api/users/:userId/team').get({ userId: userId }, function(team) {
      console.log('team: ', team);                
  }, function(err) {
      console.log('err: ', err);
  });
  </code></pre>
  
  <p>The value of team (the parameter to the success callback) is:</p>
  
  <pre><code>$promise: Object
      catch: function (callback) {
      finally: function (callback) {
      then: function (callback, errback, progressback) {
      __proto__: Object
      $resolved: true
  __proto__: Resource
      $delete: function (params, success, error) {
      $get: function (params, success, error) {
      $query: function (params, success, error) {
      $remove: function (params, success, error) {
      $save: function (params, success, error) {
      constructor: function Resource(value) {
      __proto__: Object
  </code></pre>
  
  <p>Why is the success callback getting a $promise and not an object?</p>