Remove Update Notification (for all users except ADMIN)

this works fine for a specific user login:

 global $user_login;
   get_currentuserinfo();
   if ($user_login !== "admin") { // change admin to the username that gets the updates
    add_action( 'init', create_function( '$a', "remove_action( 'init', 'wp_version_check' );" ), 2 );
    add_filter( 'pre_option_update_core', create_function( '$a', "return null;" ) );
   }

and this for a specific user id:

global $user_ID;
   get_currentuserinfo();
   if ($user_ID !== 1) { // change 1 to the id number that gets the updates
    add_action( 'init', create_function( '$a', "remove_action( 'init', 'wp_version_check' );" ), 2 );
    add_filter( 'pre_option_update_core', create_function( '$a', "return null;" ) );
   }