title: Django-Grappelli: Reverse for 'grp_related_lookup' with arguments '()' and keyword arguments '{}' not found
body: <p>I use django-grappelli to create orderable inlines on the admin site. Occasionally (not reproducibly - about 50% of the time, which is particularly weird), Django throws the following exception when I try to save the ordering from the inline:</p>
  
  <pre><code> Exception Type: NoReverseMatch
   Exception Value: Reverse for 'grp_related_lookup' with arguments '()' and keyword arguments '{}' not found.
   Exception Location: /usr/local/lib/python2.7/dist-packages/django/template/defaulttags.py in render, line 424
  </code></pre>
  
  <p>The offending line is this:</p>
  
  <pre><code> $("#id_" + this).grp_related_fk({lookup_url:"{% url 'grp_related_lookup' %}"});
  </code></pre>
  
  <p>As per the advice given in <a href="https://stackoverflow.com/questions/7182532/django-grappelli-admin-no-reverse-match-error">this related thread</a>, I've tried quickly testing it in the shell, but it seems to work fine:</p>
  
  <pre><code>&gt;&gt;&gt; from django.core.urlresolvers import reverse
  &gt;&gt;&gt; print reverse('grp_related_lookup')
  /grappelli/lookup/related/
  </code></pre>
  
  <p>I'm at a loss. Has anyone made a similar experience?</p>
  
  <p>Django version is 1.5.1.</p>