Add four passes to the pkd tests to exercise codepaths where an
OpenSSH client requests these HostKeyAlgorithms combinations:
* rsa-sha2-256
* rsa-sha2-512
* rsa-sha2-256,rsa-sha2-512
* rsa-sha2-512,rsa-sha2-256
The tests demonstrate that the third combination currently fails:
libssh ends up choosing `rsa-sha2-512` instead of `rsa-sha2-256`,
and the initial exchange fails on the client side citing a signature
failure.
Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>