Deleting unused private member variable from AphrontRequest

Summary: I was poking around to see how this class worked and noticed this variable does nothing.

Test Plan: Careful inspection and reasoning that unused private member variable can be deleted.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3068

src/aphront/AphrontRequest.php

@@ -38,7 +38,6 @@ final class AphrontRequest {
   private $path;
   private $requestData;
   private $user;
-  private $env;
   private $applicationConfiguration;
 
   final public function __construct($host, $path) {