Revoked key (lisp/epa.el)

[CHENG Gao]

In lisp/epa.el, epa-list-keys should add status for revoked key as

r revoked key.

,----
| ;;;###autoload
| (defun epa-list-keys (&optional name)
|   "List all keys matched with NAME from the public keyring."
|   (interactive
|    (if current-prefix-arg
|        (let ((name (read-string "Pattern: "
|                               (if epa-list-keys-arguments
|                                   (car epa-list-keys-arguments)))))
|        (list (if (equal name "") nil name)))
|      (list nil)))
|   (epa--list-keys name nil
|                   "The letters at the start of a line have these meanings.
| e  expired key.  n  never trust.  m  trust marginally.  u  trust ultimately.
| f  trust fully (keys you have signed, usually).
| q  trust status questionable.  -  trust status unspecified.
|  See GPG documentation for more explanation.
| \n"))
`----