Revert "Release 331.20-0ubuntu3"

This reverts commit 79d69989e10a84283387e1ce73c1290b4eb1b98b.
debian/preinst: remove leftover /usr/lib/nvidia-settings 2nd try
Release 331.20-0ubuntu3
Start work on 331.20-0ubuntu4
debian/preinst: clean up any nvidia_settings_conf alternatives
Release 331.20-0ubuntu4