mkimage-yum.sh has a lot in common with mkimage-rinse.sh, including extra
files clean up. Sync with mkimage-rinse.sh by removing yum cache to reduce
the image size.
Minor changes to reduce also the delta/diff and make it easier to sync with
mkimage-rinse.sh script.
Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Upstream-commit: 3e9fc478aebee8d4c3dd96e150e6af450dfe9350
Component: engine