drop unused code from delete_cert
drop unused code from delete_cert

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