bug#18513: 24.3; message-mode sends unencrypted on error

[Glenn Morris]

Daiki Ueno wrote:

> I've installed the following simple fix in the trunk.  Does it work for you?
[...]
> -              (setq tags (list "sign" method "encrypt" method))))
> +              (setq tags (list "sign" method "encrypt" method)))
> +             (t
> +              (error "Unknown secure mode %s" mode)))

Seems like a safe, simple fix for a potentially important issue;
so what do you think about putting it in emacs-24?