Remove support for GitHub post-receive notifications

Summary:
  - These never actually did anything.
  - I don't even really remember why I built them, maybe the Open Source team
was pushing for more GitHub integration or something? I really have no idea.
  - Anyway, repository tailers do everything these could do (and much more).

Test Plan:
  - Ran tailers off GitHub for many months without needing post-receive hooks.
  - Grepped for relevant strings, couldn't find any references.
  - Used "Repository" edit interface for a Git repository.

Reviewers: btrahan, jungejason

Reviewed By: jungejason

CC: aran, jungejason

Maniphest Tasks: T706

Differential Revision: https://secure.phabricator.com/D1273

src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php

@@ -173,9 +173,6 @@ class AphrontDefaultApplicationConfiguration
 
       '/T(?P<id>\d+)$' => 'ManiphestTaskDetailController',
 
-      '/github-post-receive/(?P<id>\d+)/(?P<token>[^/]+)/$'
-        => 'PhabricatorRepositoryGitHubPostReceiveController',
-
       '/repository/' => array(
         '$'                     => 'PhabricatorRepositoryListController',
         'create/$'              => 'PhabricatorRepositoryCreateController',