Fixes #5259 Getting $config object in autocomplete.php so that errors trace is shown

Among other problems which might get fixed by this

html/autocomplete.php

@@ -72,6 +72,7 @@ if (isset($_GET['type']) && $_GET['type'] == "base") {
 } else {
 
   $ui = session::global_get('ui');
+  $config = session::global_get('config');
 
   /* Is there a filter object arround? */
   if (session::is_set('autocomplete')) {