We added UUID device file existance check on #11399, we expect UUID
device file is created before checking, and we wait for the creation by
"udevadm settle" after "mkfs.xfs".
However, we actually getting error which says UUID device file missing,
it probably means "udevadm settle" doesn't guarantee the device file created,
on some condition.
To avoid the error, use var-lib-scylla.mount to wait for UUID device
file is ready, and run the file existance check when the service is
failed.
Fixes#11617Closes#11666
a938b009ca