Fixed telemetry error if HTTP_ACCEPT_LANGUAGE is not specified

telemetry.php

@@ -3,7 +3,7 @@ include_once('telemetry_settings.php');
 
 $ip=($_SERVER['REMOTE_ADDR']);
 $ua=($_SERVER['HTTP_USER_AGENT']);
-$lang=($_SERVER['HTTP_ACCEPT_LANGUAGE']);
+$lang=""; if(isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) $lang=($_SERVER['HTTP_ACCEPT_LANGUAGE']);
 $dl=($_POST["dl"]);
 $ul=($_POST["ul"]);
 $ping=($_POST["ping"]);