The flexible KFLAVOURS handling has a downside:
if no packages match the regexp it's silently OK
until too late, and the error is incomprehensible.
Let's fix the latter at least.

There's much reason for reuse instead of duplication
among the different stage2-based subprofiles.

In particular, the rather monolithic driver cleanup script
of the ancient is better done in several clear pieces with
the final depmod run.

Scripts dropping apt/rpm databases will dump pkglist first.

A script purging /boot/* will honour live-install if present.

Minor inno^Wfixups all over the map too.