MDL-39759 REST SERVER HTTP response code

Moodle should response 403 if web service or REST protocol not enabled

webservice/rest/server.php

@@ -37,6 +37,7 @@ require('../../config.php');
 require_once("$CFG->dirroot/webservice/rest/locallib.php");
 
 if (!webservice_protocol_is_enabled('rest')) {
+    header("HTTP/1.0 403 Forbidden");
     debugging('The server died because the web services or the REST protocol are not enable',
         DEBUG_DEVELOPER);
     die;