RSS feed date time is now expressed as iso8601

app/views/events/index.rss.builder

@@ -1,6 +1,6 @@
 def meta(xml, event)
   xml.dc :identifier, "#{event.id}@#{request.domain}"
-  xml.dc :date, l(event.start_time, format: :xml)
+  xml.dc :date, event.start_time.iso8601
 
   return unless event.latitude || event.longitude
   xml.georss :point, event.latitude, ' ', event.longitude