Comment 1 for bug 1719169

This comman will reinstall /etc/hp/hplip.conf:
sudo apt-get install --reinstall -o Dpkg::Options::="--force-confmiss" libsane-hpaio

No idea why it has been placed in another package, found the solution here: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=904070