Make SSH host key loading more consistent over time

If the site starts out with a Java formatted "ssh_host_key" file,
but later installs BouncyCastle Crypto, we should continue to use
its existing Java formatted host key, to prevent needing to do a
host key change.

Only one host key (RSA or DSA) is actually required to load the
server and make it functional for clients.  Rather than try to
require both keys at server startup we only load ones which are
available on disk.

Signed-off-by: Shawn O. Pearce <sop@google.com>
2 files changed