Covert old "boot" line to new format..

Should there be a mechanism for passing command-line options to modules,
or is this handled somewhere else (e.g., /etc/modules.conf)?

Add debconf support, for choosing which scans to disable and enable.

Generate paths (e.g., /etc/discover.conf, /lib/discover/discover, etc.)
from prefix.

update-initrd: Remove temporary files if interrupted.

When to remove /boot/initrd-VERSION?
