Remove empty implementations of describeAutomaticCapabilities()

Summary:
This has been replaced by `PolicyCodex` after D16830. Also:

  - Rebuild Celerity map to fix grumpy unit test.
  - Fix one issue on the policy exception workflow to accommodate the new code.

Test Plan:
  - `arc unit --everything`
  - Viewed policy explanations.
  - Viewed policy errors.

Reviewers: chad

Reviewed By: chad

Subscribers: hach-que, PHID-OPKG-gm6ozazyms6q6i22gyam

Differential Revision: https://secure.phabricator.com/D16831

src/applications/oauthserver/storage/PhabricatorOAuthServerClient.php

@@ -83,10 +83,6 @@ final class PhabricatorOAuthServerClient
     return false;
   }
 
-  public function describeAutomaticCapability($capability) {
-    return null;
-  }
-
 
 /* -(  PhabricatorApplicationTransactionInterface  )------------------------- */