Separate cleanly special publications in side bar

mainsite/templates/sidebar.html

@@ -13,10 +13,13 @@
     </li>
   </ul>
 
+  {% if has_special_publications %}
   <ul class="nav nav-sidebar">
-    {% if has_special_publications %}
     <li><a href="{% url "special_publications" %}">Numéros spéciaux</a></li>
-    {% endif %}
+  </ul>
+  {% endif %}
+
+  <ul class="nav nav-sidebar">
 
     {% for pubyear in publication_years %}
     <li><a href="{{ pubyear.url }}">{{ pubyear.prettyName }}</a></li>