title: bindFactory does not inject fields
body: <p>I have this code to provide a custom injectable object:</p>
  
  <pre><code>    config.register(new AbstractBinder() {
          @Override
          protected void configure() {
              delegatorFactory = ...; //custom factory to delegate to
              bindFactory(new Factory&lt;Object&gt;() {
                  @Inject
                  private Provider&lt;ContainerRequestContext&gt; req;
  
                  @Override
                  public void dispose(Object arg0) {
                  }
  
                  @Override
                  public Object provide() {
                      // req is needed but is null
                  }
              }).to(delegatorFactory.getType()).in(RequestScoped.class);
          }
      });
  </code></pre>
  
  <p>Unfortunately, as the comment in provide() reveals, the <code>req</code> field is not injected when it is executed (I need the <code>ContainerRequestContext</code> at that location).
  What am I missing to make it work like this, i.e. make the factory's fields injected?</p>