Fix incorrect return code on ECDSA key verification

Fix incorrect return code on ECDSA key verification

ECDSA_do_verify() is a function that verifies a ECDSA signature given a hash and a public EC key. The function is supposed to return 1 on valid signature, 0 on invalid signature and -1 on error. Previously, we returned 0 if the key did not have a verify_sig method. This is actually an error case and not an invalid signature. Consequently, this patch updates the return code to -1.

Fixes #8766

Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/10693)