Revert "properly pad challenge-response with shorter than 64 byte challenge"
Revert "properly pad challenge-response with shorter than 64 byte challenge"

This reverts commit 27a2fbd772a29136ccaac8b65747df1b6e6e0fd3.

This commit is wrong since the padding should only be done in the case
when hmac-lt64 is set and that is unknown to the API. Thus padding like
this must be done from the calling application that might know more
about it's requirements.

Yubico/yubikey-personalization,Yubico/yubikey-personalization-dpkg,Yubico/yubikey-personalization-dpkg,eworm-de/yubikey-personalization,eworm-de/yubikey-personalization,Yubico/yubikey-personalization,Yubico/yubikey-personalization-dpkg,eworm-de/yubikey-personalization