Remove differential.anonymous-access

Summary:
Fixes T3034. This is obsoleted by modern policies.

This was written by a Facebook intern and is rarely used -- the Hive install might be the only use in the wild. It has never really worked correctly.

Test Plan: `grep`; browsed Differential.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3034

Differential Revision: https://secure.phabricator.com/D7568

src/applications/differential/controller/DifferentialController.php

@@ -2,10 +2,6 @@
 
 abstract class DifferentialController extends PhabricatorController {
 
-  protected function allowsAnonymousAccess() {
-    return PhabricatorEnv::getEnvConfig('differential.anonymous-access');
-  }
-
   public function buildApplicationCrumbs() {
     $crumbs = parent::buildApplicationCrumbs();