Using set -e in all of our scripts will prevent some subtle bugs
from slipping in, and will allow us to enforce use of set -e with
tooling.
This change also adds -u and set -o pipefail in the less complex
scripts where it is unlikely to cause problems. A follow-up change
will enable those options in the complex scripts so that if it
breaks something it can be reverted easily.
Change-Id: I0ad358ccb98da7277a0ee2e9ce8fda98438675eb
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
