Revert "Require grubby its needed by kernel-install"
This reverts commit 014067a71aa47ea603c98ad97aae415e31362c77.
kernel-install does *not* require grubby, and is not supposed to.
Grubby is already included in comps, and if really needed it should
be pulled-in by grub and friends, not by systemd which would
unconditionally always pull it into every installation.