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
Bug 1124593 reported that ssh host keys were not being created, and the
lack of seed metadata files was the cause. Add those files and remove
the workaround.
Change-Id: I6fb55be7f8c7efd1f75aeba9123f495e312ff695
