title: Symfony2 entity field displaying all entries when choices are empty
body: <p>I have an entity type form field in my Symfony2 project.  </p>
  
  <pre><code>$builder = $this-&gt;createFormBuilder();
  $projects = $this-&gt;getProjects();
  
  $builder-&gt;add('project', 'entity',
          array(
              'class' =&gt; 'MyBundle:Project',
              'required' =&gt; false,
              'choices' =&gt; $projects,
          ));
  </code></pre>
  
  <p>The problem I'm having is, when the <code>getProjects()</code> method will return an empty result set, the drop down list will have <em>all</em> the projects in the Project table.</p>
  
  <p>Is there any way to disable this behavior?</p>