use section name instead of section for box slugs

symposion/templates/schedule/schedule_detail.html

@@ -22,7 +22,7 @@
             </div>
         </div>
         <div class="span12">
-            {% box "schedule_top_"|add:schedule.section|slugify %}
+            {% box "schedule_top_"|add:schedule.section.name|slugify %}
             
             {% cache 600 "schedule-table" schedule.section %}
                 {% for timetable in days %}