Comment 8 for bug 1469204

https://anonscm.debian.org/cgit/docker/docker.io.git/commit/?id=0bc5ad426c84804c939804e33247140ff2636991 is the compromise I've applied in Debian recently (replacing the file's contents with a long-form note pointing our users to the upstream-recommended alternatives, which should invoke dpkg's configuration file merge and also not break existing users right away).