It seems that our nodepool is configured with the ecdsa and ed25519 host
keys from the nodepool nodes, but not the rsa or dsa keys. This is a
problem when we try to test our puppet SSH configuration in CI, because
the puppet module removes the ability for the Zuul executor to reach the
node and perform cleanup tasks after the tests have completed.
This patch adds back the HostKey settings that the nodepool images
started out with. This should not affect the puppetmaster's or a
rooter's ability to log into production servers that are already using
an rsa host key.
Change-Id: I150b76a632398d0a6f00d5b98ad7277c62377601
277e41829d