Comment 24 for bug 8585

I think we better find out the rationale for that change in checkroot. On my
fairly stale (~3 months) sid system, checkroot only does

if [ "$rootmode" = rw ]
then
        [ ! -L /etc/mtab ] && [ -f /etc/mtab~ ] && rm -f /etc/mtab~
        : > /etc/mtab
        mount -f -o remount /
        mount -f /proc
        [ -n "$devfs" ] && mount -f $devfs
fi

So it must've changed recently or perhaps only in Ubuntu.