say Not Yet Rated if we don't have ratings (bug 634758)

apps/addons/templates/addons/listing/items_mobile.html

@@ -22,6 +22,8 @@
             {% with num=addon.total_reviews %}
               {% if num %}
                 {{ addon.average_rating|float|stars }}
+              {% else %}
+                <i>{{ _('Not Yet Rated') }}</i>
               {% endif %}
             {% endwith %}
           {% endif %}

media/css/zamboni/mobile.css

@@ -55,6 +55,11 @@ table {
 }
 */
 
+i {
+    font-style: italic;
+    color: #838382;
+}
+
 /** Clearfix */
 .listview li a:after,
 header:after,
@@ -1375,4 +1380,4 @@ footer a.desktop-link {
     margin: 1em 0;
     text-align: center;
     text-transform: uppercase;
-}
+}