git-annex refuses to use revoked GPG keys. This may be understandable for the initial remote setup, but it hit me when I tried to add a new key to a remote. The previous key has been revoked (because it has been superseded by the new one), and git-annex refused to reinvoke the shared key with both keys because one of them was revoked.
Given the encryption model does not allow key replacement, it should not refuse to reencrypt using a revoked key. Maybe using `--expert` would help.
### What steps will reproduce the problem?
Encrypt a special remote with a key K1. Revoke key K1. Try to add key K2 with enableremote. git-annex will refuse to encrypt the shared key with the revoked one.
### What version of git-annex are you using? On what operating system?
git-annex version: 4.20130802-g1452ac3
### Please provide any additional information below.