title: RPC Cookie error in gwtp-sample-basic-spring example
body: <p>I cloned <a href="https://github.com/ArcBees/GWTP-Samples/tree/master/gwtp-samples/gwtp-sample-basic-spring" rel="nofollow">this example</a></p>
  
  <p>When running it, I get the following error </p>
  
  <blockquote>
    <p>An error occured: Cookie provided by RPC doesn't match request cookie, 
        aborting action, possible XSRF attack. (Maybe you forgot to set the
        security cookie?) While executing action:
           com.gwtplatform.samples.basicspring.shared.dispatch.SendTextToServerAction</p>
  </blockquote>
  
  <p>How to fix this?</p>