bug#26359: 25.2; smtpmail.el tries useless unauthenticated connection

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Fri, 26 Jul 2019 12:17:25 +0200
> Cc: 26359@debbugs.gnu.org
> 
> I've now added smtpmail-servers-requiring-authorization to the
> trunk.

Please add a :version tag to it.

Thanks.