bug#4080: 23.1.50; Message-mode doesn't handle YANK-ACTION argument of COMPOSE-MAIL

[Chong Yidong]

> Command compose-mail has an optional sixth argument YANK-ACTION which
> defines what to do when user presses C-c C-y (mail-yank-original) in
> mail-mode buffer.
>
> However, this does not work when mail-user-agent is
> "message-user-agent" or "gnus-user-agent". Message-mode has C-c C-y
> (message-yank-original) command but it does not do anything.

Thanks for the report.  I've checked in a fix for this shortcoming of
message-mode.