
If we attempt to push a mirror to a host we've never connected to before, it won't be in the SSH known hosts and the mirror will fail. This makes a new host_key parameter required and the role takes care of setting it up in the known_hosts for the duration of the job. Change-Id: I4bd40a289003fe3e88c9af4029576236c064fc3d Depends-On: https://review.openstack.org/#/c/649183/