Route/Part.pm: Fix departure_stop_and_platform (closes github #3)

Changelog

+git HEAD
+
+    * Fix bug in departure_stop_and_platform where the arrival_stop was used
+      in case of unknown platforms
+
 Travel::Routing::DE::VRR 2.00 - Sun Dec 11 2011
 
     * Now uses the efa.vrr.de XML interface

lib/Travel/Routing/DE/VRR/Route/Part.pm

@@ -44,7 +44,7 @@ sub departure_stop_and_platform {
 		  sprintf( '%s: %s',
 			$self->get(qw(departure_stop departure_platform)) );
 	}
-	return $self->arrival_stop;
+	return $self->departure_stop;
 }
 
 sub extra {