Subject: [Acme] Add rejectedIdentifier error type

From: Jacob Hoffman-Andrews <[email-masked]>
Date: Tue, 21 Jun 2016 11:28:45 -0700

I've submitted a pull request to add a new rejectedIdentifier error
type, for malformed and blacklisted names:

https://github.com/ietf-wg-acme/acme/pull/142