bug#34663: remove ftx font backend

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Cc: 34663@debbugs.gnu.org
> Date: Wed, 15 Jan 2020 20:06:21 +0100
> 
> > Btw, I think we should remove admin/notes/font-backend instead of
> > continuing its maintenance.  It is already outdated, and I don't
> > really see how it could be useful even if we update it to mention
> > HarfBuzz etc.
> 
> OK.  I've attached a patch.
> 
> Do you want this installed on master or the release branch?

The latter.  Thanks.