do_challenge_response: Clear errno when done.
do_challenge_response: Clear errno when done.

eworm-de/yubico-pam,Yubico/yubico-pam,madrat-/yubico-pam,Yubico/yubico-pam,Yubico/yubico-pam,madrat-/yubico-pam,eworm-de/yubico-pam,eworm-de/yubico-pam,madrat-/yubico-pam