title: How to reset form in Symfony
body: <p>How can I reset the form after submit? It's a simple search form where I show a field on the top and a table in the bottom that shows either the results based on the search or the whole list... but it does not reset, the search key remained... </p>
  
  <pre><code>/**
   * @Route("/", name="plazas_index")
   */
  public function indexAction(Request $request)
  {
      $form = $this-&gt;createForm('AppBundle\Form\BuscarType');
      $form-&gt;handleRequest($request);
  
      $repository = $this-&gt;getDoctrine()-&gt;getRepository('AppBundle:Plaza');
  
      if ($form-&gt;isSubmitted() &amp;&amp; $form-&gt;isValid()) {
  
          $clave = $form['clave']-&gt;getData();
  
          $query = $repository-&gt;createQueryBuilder('p')
              -&gt;where('p.nombre LIKE :nombre')
              -&gt;orWhere('p.localidad LIKE :localidad')
              -&gt;setParameter('nombre', '%'.$clave.'%')
              -&gt;setParameter('localidad', '%'.$clave.'%')
              -&gt;orderBy('p.nombre', 'ASC')
              -&gt;getQuery();
  
          $plazas = $query-&gt;getResult();
          $cant = count($plazas);
  
          $this-&gt;addFlash($cant ? 'success' : 'warning', 'La búsqueda de '.$clave. ' ha producido '.$cant.' resultados');
          //return $this-&gt;redirectToRoute('plazas_index');
      }
      else {
          $plazas = $repository-&gt;findAll();
      }
  
      unset ($form);
      $form = $this-&gt;createForm('AppBundle\Form\BuscarType');
      $form-&gt;handleRequest($request);
      return $this-&gt;render('admin/plazas/index.html.twig', array(
          'plazas' =&gt; $plazas,
          'buscar_form' =&gt; $form-&gt;createView(),
      ));
  }
  </code></pre>
  
  <p>I can't redirect because I do the render at the end of the action...
  Any help is welcome, thanks!!</p>