Comment 7 for bug 1307546

I think it's likely the nvidia prime postrm script that did it.

snippet:

case "$1" in
    purge|remove|upgrade|failed-upgrade|abort-install|abort-upgrade|disappear)
        # Remove the xorg.conf
        if [ -f $xorg_conf ]; then
            mv $xorg_conf $xorg_conf.$now
        fi