Add a test case to verify that the server returns the correct signature
when it negotiated an RSA signature algorithm for the host key different
from the one it prefers (e.g. when the client prefers ssh-rsa over
rsa-sha2-256 and rsa-sha2-512).
Fixes T240
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
7aad964cef