3rd code block in Guides, section "Rendering a Template" fails

This used to work in version [ember-1.0.0-pre.4.js](https://raw.github.com/emberjs/ember.js/release-builds/ember-1.0.0-pre.4.js) as illustrated in this [JSFiddle](http://jsfiddle.net/oldfartdeveloper/WjYdn/2/).

However, **I've added a test** in this pull request that demonstrates that this no longer works in the latest master.  If you specify just the value for the custom-named controller, it works fine; however, if you use the key/value pair as shown in the 3rd code block of the latest [guides](https://github.com/emberjs/website/blob/master/source/guides/routing/rendering-a-template.md), it fails.  I repeat the failing code block for your convenience:

    App.PostsRoute = Ember.Route.extend({
      renderTemplate: function() {
        this.render({ controller: 'favoritePost' });
      }
    });

This is related to another issue, #2027, that applies to "pre.4", but I think this problem takes precedence.