title: Objectify 4 Filter not working
body: <p>I'm trying to do a simple JUnit test to do a query like this:           </p>
  
  <pre><code>Resource result = ofy().load().type(Resource.class).filter("raw =", 
      "/Bob/-/userId/-/").first().get(); 
  if (result != null){
      System.out.println("Resulting Resource raw =" + result.getRaw());
  } 
  </code></pre>
  
  <p>The query above results to <code>null</code>, however when I do a query using id (which is a Long type) I get the result. When I persisted the entity I'm trying to 
  query I logged the <code>@Id</code> and the value is <code>1</code>, so I did a query using <code>id</code> to check:</p>
  
  <pre><code>Resource result = 
      ofy().load().type(Resource.class).filter("id =", 1).first().get(); 
  if (result != null){
      System.out.println("Resulting Resource raw =" + result.getRaw());
  }
  </code></pre>
  
  <p>The resulting <code>result.getRaw()</code> is <code>/Bob/-/userId/-/</code> which is really weird, from my first query the result should have not been <code>null</code>?</p>