nbd devices doesn't quite make sense to be probed

[Dimitri John Ledkov]

Found Ubuntu Eoan Ermine (development branch) (19.10) on /dev/nbd0p1

I have qemu-nbd cloud image mounted at /dev/nbd0 hence 19.10 is detected on nbd0p1

However, given that it is ~= loop mount, it doesn't really make sense to grub detect it, as it's not directly bootable by grub.

It generated an entry, but it would not be bootable

menuentry 'Ubuntu Eoan Ermine (development branch) (19.10) (on /dev/nbd0p1)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'osprober-gnulinux-simple-7dcf60b9-33c7-42a1-bbf1-2b930917b6d7' {
        insmod part_msdos
        insmod ext2
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root 7dcf60b9-33c7-42a1-bbf1-2b930917b6d7
        else
          search --no-floppy --fs-uuid --set=root 7dcf60b9-33c7-42a1-bbf1-2b930917b6d7
        fi
        linux /boot/vmlinuz-5.0.0-1008-kvm root=PARTUUID=bc7dd985-01 ro console=tty1 console=ttyS0 panic=-1
        initrd /boot/initrd.img-5.0.0-1008-kvm
}

[Sebastien Bacher (seb128)]

Could you report that to the Debian BTS?