14->15 upgrade comments

[Alan Cox]

> blue and white progress bars were making their way across the screen.
> I do not know howto capture the stacktrace. The machine freezes.
> Ctl-Alt-Del does not cause a reboot. The offswitch does not work.

If the box goes castors up it's fairly hard to capture it. You pretty
much have to write it down (or take a photo of it) and transcribe it
later.

The photo is actualyl a pretty good approach as you can then reboot the
system and get it back in service fast.

Alan