[HttpFoundation] Fixed duplicate of request

closes #2133

src/Symfony/Component/HttpFoundation/Request.php

@@ -284,15 +284,15 @@ class Request
             $dup->server = new ServerBag($server);
             $dup->headers = new HeaderBag($dup->server->getHeaders());
         }
-        $this->languages = null;
-        $this->charsets = null;
-        $this->acceptableContentTypes = null;
-        $this->pathInfo = null;
-        $this->requestUri = null;
-        $this->baseUrl = null;
-        $this->basePath = null;
-        $this->method = null;
-        $this->format = null;
+        $dup->languages = null;
+        $dup->charsets = null;
+        $dup->acceptableContentTypes = null;
+        $dup->pathInfo = null;
+        $dup->requestUri = null;
+        $dup->baseUrl = null;
+        $dup->basePath = null;
+        $dup->method = null;
+        $dup->format = null;
 
         return $dup;
     }