[pkg-gnupg-maint] Bug#850982: Bug#850982: Add instructions to disable gpg-agent user service in README.Debian

[Yuri D'Elia]

On Wed, Jan 11 2017, Daniel Kahn Gillmor wrote:
>> I do not want to auto-start these services for the root user. I also want to
>> disable auto-start completely in servers I'm logging into. I think both are
>> pretty common scenarios and deserve special mention, as systemctl --user
>> disable won't work some might expect.
>
> fwiw, nothing is auto-started at all -- the systemd user session opens
> the sockets, but doesn't launch any daemons if the sockets are never
> used.
>
> Put in more systemd-ish terms: it's the .socket units which are
> automatically enabled, not the .service units.
>
> does that change what you want to happen?

Listening is still not a good idea in these cases. For instance, any
command that probes the agent will start it as a result. This might be
especially annoying for ssh, as there is still the choice between the
gpg agent, ssh-agent, and nothing at all.

I also don't think that these services make any sense for root (or more
generally, any system user). Is there a way to restrict the unit?

I'm also not entirely sure on the best way to disable the socket. Should
you mask it?