If systemctl fails to start boot.mount to mount the /boot partition,
emit a warning message and wait 5 seconds for user to cancel. Don't
treat as fatal just in case this is a non-typical installation.
Also fixes a minor typo elsewhere.
Let's try first fall back to find the efivar from LoaderDevice
mount it by /dev/disk/by-partuuid, BUT first lowercase the partuuid.
and then this solution.