fix farplan url

_layouts/frab.xml

@@ -179,7 +179,7 @@ Finding the first and last talk to establish the variables "earliest" and "lates
 
 	{% if video.fahrplan_url and video.fahrplan_url  != ''-%}
 		{% if video.fahrplan_url contains "https://" -%}
-			{% assign url =  video.url -%}
+			{% assign url =  video.fahrplan_url -%}
 		{% else -%}
 			{% if conference.base_url contains "https://chaotikum.org" -%}
 			{% capture url %}https://chaotikum.org{{video.url}}{% endcapture -%}