Similar to the CentOS-9-Stream fix [1] this change renames the default
BLS entry to match the current machine-id so that grub2-mkconfig calls
will refresh the kernel options.
However there is an additional issue with the rhel-9 base image. It is
unique in having a dedicated boot partition, so the path to the kernel
and initramfs don't include /boot. This results in an unbootable image
when /boot is a directory of the root partition.
These paths do not get corrected by calling grub2-mkconfig, so this
change performs a sed on the paths to fix them for a root partition
/boot.
[1] I327f5e7a95e47905c01138c8c4483f3f03e8efff
Change-Id: I37a1d310e1854f4a49725e355d484e456ea4fc7a
4376f66407