CC-2569 : Scheduling a rebroadcast show uses old file length access

use new metadata key access.

airtime_mvc/application/models/Schedule.php

@@ -56,7 +56,7 @@ class ScheduleGroup {
 
             // Check if there are any conflicts with existing entries
             $metadata = $track->getMetadata();
-            $length = trim($metadata["length"]);
+            $length = $metadata['MDATA_KEY_DURATION'];
             if (empty($length)) {
                 return new PEAR_Error("Length is empty.");
             }