OpenSSH agent has a bug which makes it to not use SHA2 in signatures
when using certificates. It always uses SHA1.
See https://gitlab.com/libssh/libssh-mirror/merge_requests/34
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>