Update course.

Signed-off-by: Willy Sudiarto Raharjo <willysr@gmail.com>

courses.php

@@ -29,7 +29,6 @@ include "includes/navbar.html";
   <ol>
     <li><a href="manpro-ti/index.php">Project Management</a></li>
     <li><a href="kakom-ti/index.php">Computer Security</a></li>
-    <li><a href="kripto-ti/index.php">Cryptography</a></li>
     <li><a href="os-ti/index.php">Operating System</a></li>
   </ol>
 </article>