Fix a redirect loop when a user with an expired CAS session tried to transparently log in.

library/Unl/Controller/Action/Authenticate.php

@@ -84,7 +84,7 @@ abstract class Unl_Controller_Action_Authenticate extends Unl_Controller_Action
             $this->_setupUser(Zend_Auth::getInstance()->getIdentity());
         } else {
             Zend_Auth::getInstance()->clearIdentity();
-            if (!isset($_COOKIE['unl_sso'])) {
+            if (isset($_COOKIE['unl_sso'])) {
                 setcookie('unl_sso', 'fake', time() - 60*60*24, '/', '.unl.edu');
             }
         }