title: Django "with" template tag renders empty for ForeignKey relationship
body: <p>I was using the <code>count</code> method on a queryset context variable more than once in a template, so I decided to store it in a reusable variable:</p>
  
  <pre><code>{% with album.photograph_set.count as numPhotos %}
      &lt;title&gt;My title with {{ numPhotos }} in it&lt;/title&gt;
      &lt;span&gt;I use {{ numPhotos }} here, too&lt;/span&gt;
  {% endwith %}
  </code></pre>
  
  <p>The <code>numPhotos</code> variable always seems to be blank, though replacing it with <code>album.photograph_set.count</code> inline still returns the appropriate value. I also tried using the <code>{% with numPhotos=album.photograph_set.count %}</code> syntax but it exhibits the same behavior. I use the <code>{% with ... as ... %}</code> syntax elsewhere in my code and it works as expected.</p>
  
  <p>Any help is appreciated.</p>