Comment 2 for bug 1566333

So the situation is that the old cron (https://launchpad.net/ubuntu/+source/cron/3.0pl1-124ubuntu2/+build/4287213/+files/cron_3.0pl1-124ubuntu2_amd64.deb) just ships the symlink in the .deb, and the new cron ships the plain file, and dpkg apparently refuses to replace a symlink with a file. This is currently not handled in the maintainer scripts at all, so we need to add some upgrade logic.