Remove RedHat grub workaround install

AFAICT this is no longer necessary.  I've tested minimal and image
builds and they seem to work.

The original problem seems to be with installing the package in the
chroot, although it was never quite clear it ever affected the Red Hat
path.

This code is currently broken (see
I884cb1e78ad8c31d985f3fc94a58091b993edd7d).  This is proposed as an
alternative to I74eed074494134334d5e49042bb5214bd0dd7339.

Related-Bug: #1627000

Change-Id: Iafe3611f4eec3c6357587a6cae6a30a261686ead

elements/redhat-common/package-installs.yaml

@@ -6,14 +6,3 @@ traceroute:
 which:
 gettext:
     phase: pre-install.d
-
-# these are being installed to satisfy the dependencies of grub2.  See
-# 15-remove-grub for more details
-grub2-tools:
-    phase: pre-install.d
-os-prober:
-    phase: pre-install.d
-redhat-lsb-core:
-    phase: pre-install.d
-system-logos:
-    phase: pre-install.d