libssl: don't reach for pkey->save_type.
For some strange historical reason ECDSA_sign() and ECDSA_verify}() have
a type argument that they ignore. For another strange historical reason,
the type passed to them from libssl is pkey->save_type, which is used to
avoid expensive engine lookups when setting the pkey type... Whatever the
aforementioned reasons were, we can't access pkey->save_type with the
OpenSSL 1.1 API, and this is thus in the way of making EVP_PKEY opaque.
Simply pass in 0 instead.
ok jsing