Expiring sent drafts does now always `delete'

[Katsumi Yamaoka <yamaoka@jpl.org>]

Hi,

This might be a regression but I think it would trouble no one.
I made draft messages come to be deleted after being sent regardless
of the value of `nnmail-expiry-target'.  If it is `delete', that
is the default, the behavior is unchanged.  Before this change,
a sent draft was moved to an expiry group if `nnmail-expiry-target'
specifies it.  However, there were some problems with moved drafts:

1. A separator is left between the header and the body.  It causes
   the body of a moved draft to be unable to read.

   Even if one sets or binds `mail-header-separator' to "",

2. A message is in MML, not MIME.  I.e., non-ASCII text is as is,
   attachments are mere tags.
3. There seems to be an unresolved bug.

See also:
http://article.gmane.org/gmane.emacs.gnus.user/16110
http://article.gmane.org/gmane.emacs.gnus.user/16114
http://article.gmane.org/gmane.emacs.gnus.user/16160
http://article.gmane.org/gmane.emacs.gnus.user/16163
http://article.gmane.org/gmane.emacs.gnus.user/16164
http://article.gmane.org/gmane.emacs.gnus.user/16165
http://article.gmane.org/gmane.emacs.gnus.user/16166
(The thread is broken because info-gnus-english@gnu.org rewites
 Message-IDs. :<)

There are similar problems with draft messages that are copied
or moved to normal groups by `B c' or `B m'.  But IMHO, it's not
worth improving, since you can use Gcc or something if you want
to archive sent messages.

Regards,