title: how to mock providers specified in @component meta data in angular-2.0.0-rc-4
body: <p>since, overrideProviders is not supported in angular-2.0.0-rc-4.</p>
  
  <p>i tried using</p>
  
  <pre><code>beforeEach(() =&gt; {
  addProviders([
      TestComponentBuilder,
      FeedsListComponent, {
          provide: FeedsService,
          useClass: MockFeedsService
      }
  ]);
  </code></pre>
  
  <p>});</p>
  
  <p>i am able to mock the service if it was provided at bootstrap phase.
  but if it's provided @componet level like below</p>
  
  <pre><code>@component({
   ...
   providers: ['FeedsService']
  })
  class FeedsListComponent {
  }
  </code></pre>
  
  <p>even if i used provide it's not taking the mockedService. So, is there any alternative way to mock the services specified in @component meta data instead of overrideProviders</p>