Replace ssh-keyscan with host keys from node

Now that we have the host keys of a node in zookeeper, we can drop
ssh-keyscan from zuul and simply write the data to known_hosts.

Change-Id: I7a130a9cb47d0e248b7c5d5e3d576bee58a81d73
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
3 files changed