Comment 9 for bug 1577926

@bjornmagnus
Have you tested my other debugging approach (making apt-get NOT change user)

1. running the apt-key commands from the sandbox ("_apt") user (switching users outside of apt-get)
$ sudo -u _apt apt-key --foo --bar baz

2. deleting the _apt user (making apt fall back to not switching users)
$ deluser _apt
$ apt-get -o "Debug::Acquire::gpgv=true" update
$ # you will want to undo this, see /var/lib/dpkg/info/apt.postinst:
$ adduser --force-badname --system --home /nonexistent --no-create-home --quiet _apt