Handle MACHINE_ID=uninitialized
systemd supports /etc/machine-id to be set to: uninitialized
In this case the expectation is that systemd creates a new
machine ID and replaces the value 'uninitialized' with the
effective machine id. In the scope of kernel-install we
should also enforce the creation of a new machine id in this
condition
(cherry picked from commit 305dd91adfde332e7e5c1b2470edb32774f9a032)