explicitly return false; remove reliance on $_SESSION being populated…

… (stop E_NOTICE like error thing)

git-svn-id: https://xerteonlinetoolkits.googlecode.com/svn/trunk@269 912cdd6b-5c7d-d5a7-a2ba-d0f0cdb91641

website_code/php/user_library.php

@@ -267,7 +267,6 @@ function get_user_root_folder(){
 
 
 /**
- * 
  * Function is user admin
  * Is this user set as an administrator
  * @author Patrick Lockley
@@ -276,17 +275,9 @@ function get_user_root_folder(){
  * @copyright Copyright (c) 2008,2009 University of Nottingham
  * @package
  */
-
 function is_user_admin(){
-
-    global $xerte_toolkits_site;
-
-    if($_SESSION['toolkits_logon_id']=="site_administrator"){
-
+    if(isset($_SESSION['toolkits_logon_id']) && $_SESSION['toolkits_logon_id']=="site_administrator"){
         return true;
-
     }
-
+    return false;
 }
-
-?>