[pkg-gnupg-maint] Bug#913614: gnupg2 fails with "cannot open '/dev/tty': No such device or address"

[Joseph Ferguson]

Package: gnupg
Version: 2.1.18-8~deb9u3

Reproducer, run the following in an environment without a tty.  For me, this
is happening in a "docker build".  It happens on old Docker versions as
well as new.

# apt install gnupg2 (2.1.18-8~deb9u3)
$ gpg --verbose --keyserver hkp://keyserver.ubuntu.com:80 \
  --keyserver-options timeout=5 --recv-keys \
  ABAF11C65A2970B130ABE3C479BE3E4300411886

Error text:
gpg: cannot open '/dev/tty': No such device or address

If I manually download the debs for gnupg2, dirmngr, and gnupg-agent
at '2.1.18-8~deb9u2', it works fine. I grabbed the 3 debs directly from
snapshot.debian.org and then installed them with  "apt install -V -y *.deb".

Example of full failure output (multiple times across different gpg servers):
https://travis-ci.org/boot2docker/boot2docker/builds/454166287#L1390-L1427

Thanks,
Joe Ferguson