handle empty playlist nav

tubearchivist/home/templates/home/video.html

@@ -72,6 +72,7 @@
         </div>
     </div>
 {% endif %}
+{% if playlist_nav %}
     {% for playlist_item in playlist_nav %}
         <div class="playlist-wrap">
             <a href="{% url 'playlist_id' playlist_item.playlist_meta.playlist_id %}">
@@ -107,4 +108,5 @@
             </div>
         </div>
     {% endfor %}
+{% endif %}
 {% endblock content %}