All of the yum-based install-packages scripts are doing essentially
the same thing, so let's use one script for all of the elements
that depend on the yum element.
Change-Id: I49e8c9b44e41bcf4cb9fa820e8a9179754694a97
Fix the test for $TARGET_ROOT in root.d/50-yum-cache.
Don't use $TARGET_ROOT in pre-install, it's only set for "root" and "cleanup".
Change-Id: I048364ea08ef503a4466f3494f18f72ebf99b5c2
The yum element provides for specific customizations
for yum based distros. The included customization is
a yum cache mounted outside of the chroot so that yum
downloaded packages are reused on subsequent image builds.
Change-Id: I6833c9fdbc83cb09debec6a789082e105c917800
