Comment 4 for bug 1446231

This is because we dropped some old cruft to handle migrations from console-setup << 1.55 or so; but it turns out to still be necessary.

Ubiquity doesn't set seen for the debconf questions about model and layout, which would later get noticed and the priority for those questions dropped to medium in the same code as used for preseeding. Unfortunately, since ubiquity doesn't do that (still needs fixing too, added a task for it), we need to look for XKBLAYOUT in /etc/default/keyboard for the upgrade cases and drop priority if it's there.