Bug#813007: Fix container detection (running-in-container is an Ubuntu-ism)

[Martin Pitt]

Hey Ian,

Ian Campbell [2016-01-28 16:38 +0000]:
> Will it always be installed or is a Depends needed?

ATM you can change installs to remove systemd, and on some arches
(Hurd, BSD) the systemd package isn't even available (on those it
doesn't matter though, as there are no containers either). The patch
should be robust against systemd-detect-virt not existing.

That said, systemd is part of debootstrap and installed on almost all
machines and containers these days. So this patch changes it from
"container detection is broken everywhere because running-in-container
does not exist anywhere" to "it works in most environments except
where you try hard to get rid of it".

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)