seminar_open: fixed link to calendar, fixes #3798

Closes #3798

Merge request studip/studip!2669

lib/seminar_open.php

@@ -44,7 +44,7 @@ function startpage_redirect($page_code) {
             $jump_page = "dispatch.php/contact";
         break;
         case 5:
-            $jump_page = "dispatch.php/calendar";
+            $jump_page = "dispatch.php/calendar/calendar";
         break;
         case 6:
             // redirect to global blubberstream