Switch default mount point from /lib/live/mount/medium to /run/live/medium In commit 0d878d3a679 of live-boot(-grml) ("Simplify mount point handling by using /run/live instead of /lib/live/mount") the mountpath of /lib/live/mount/medium was moved towards /run/live/medium. Commit c6a17c7b41b of live-boot(-grml) provides a backward compatibility rbind mount, but occasionally there seems to be a regression somewhere during boot (see https://github.com/grml/live-boot-grml/issues/10), and the rbind mount will be deprecated and removed before the bullseye (Debian 11) release. Layout changes over time: * /cdrom: old linuxrc approach * /live/image for initramfs layout until December 2012 * /lib/live/mount/medium for initramfs layout since December 2012 * /run/live/medium for initramfs layout since December 2018 Drop support for everything but /run/live/medium and /lib/live/mount/medium, while at it. Also noticed that save-config wasn't properly handling the location of the rootfs and overlay mount points, adjusted while at it. Closes: grml/live-boot-grml#10