title: Override permission and authentication classes in ViewSet list method
body: <p>I am trying to set specific authentication and permission classes on the ListModelMixin of a viewset. I tried the following but it is not working:</p>
  
  <pre><code>    def list(self, request):
          self.authentication_classes = (apiauth.SessionAuthentication, )
          self.permission_classes = (permissions.IsAuthenticated, )
          return super(TestViewSet, self).list(request)
  </code></pre>
  
  <p>Am i doing something wrong ?</p>