xss: Prevent Agent Directory XSS

This addresses a vulnerability where an Agent can perform XSS via the
Agent Directory’s REQUEST query string. This sanitizes the request params
so the code will be escaped and not executed in the browser.

include/staff/directory.inc.php

@@ -5,6 +5,10 @@ $qs = array();
 $agents = Staff::objects()
     ->select_related('dept');
 
+// Sanitize 'order' param To Escape XSS
+if ($_REQUEST['order'])
+    $_REQUEST['order'] = Format::sanitize($_REQUEST['order']);
+
 if($_REQUEST['q']) {
     $searchTerm=$_REQUEST['q'];
     if($searchTerm){