Bug#589532: still does not depend on xorriso, although it should

[George Danchev]

Followup-For: Bug #589532

I forgot to comment on the devscrpts use pattern, which tries to
be as flexible as possible: "install $ABC package to do $XYZ"

> The wishlist item is that perhaps grub-mkrescue should explicitly
> advise installing the xorriso package if you don't have it.

While the devscripts approach is fine for non urgent tasks devscripts 
provides, I believe a more safer approach should be taken when it comes
to tasks of creating rescue images.

There is a sutble scenario, a newbie might be trapped, when they are to 
be adviced by grub-mkrescue (while being in the middle of nowhere) to 
install xorriso and when no package repository could be reached for whatever
trivial reasons. It is quite unlikely an experienced user to be trapped like
that, but then again, they are very likely to find a decent way out.

That being said, I'd go for putting an extra safety net to guarantee the 
successful operation completion on time, by splitting another "grub-rescue"
binary package which would then depend on xorriso, to avoid subtle surprises.
This way the intentions would better match the reality, in my opinion.