auth/cas MDL-18643 CAS synchronization fails with Microsoft Active Directory

The bug was fixed in LDAP auth plugin but was not applied to CAS auth too.

Thanks to Jose Garcia for the bug report and proposed fix.

auth/cas/auth.php

@@ -488,6 +488,9 @@ if ( !is_object($PHPCAS_CLIENT) ) {
             if (!empty($this->config->version)) {
                 ldap_set_option($connresult, LDAP_OPT_PROTOCOL_VERSION, $this->config->version);
             }
+            if ($this->config->user_type == 'ad') {
+                 ldap_set_option($connresult, LDAP_OPT_REFERRALS, 0);
+            }
             if (!empty($binddn)) {
                 //bind with search-user
                 //$debuginfo .= 'Using bind user'.$binddn.'and password:'.$bindpwd;