Fix parameter check in SignInit.
Fix parameter check in SignInit.

akgood/yubico-piv-tool,akgood/yubico-piv-tool,Yubico/yubico-piv-tool,Yubico/yubico-piv-tool,akgood/yubico-piv-tool,akgood/yubico-piv-tool,Yubico/yubico-piv-tool