Encode OCSP nonce value as an octet string (RFC 6960)
* src/ocsp.c (ksba_ocsp_set_nonce): Stop removing the sign bit. (write_request_extensions): Encode nonce as octet string. (parse_response_extensions): Decode nonce as octet string.
The type of nonce value was not specified back in RFC 2560, but RFC
6960 has clarified the situation by requiring an octet string. This
is also what OpenSSL does since 0.9.7d. Doing the same improves
interoperability with some responders (and Wireshark packet dissectors).
- Signed-off-by: Tomáš Trnka <tomastrnka@gmx.com>