Tests: guarded ssl_certificates.t for old OpenSSL versions. The ssl_certificates.t test uses ECDSA ciphers, which are only available starting with OpenSSL 0.9.8b. In previous versions, notably in OpenSSL 0.9.8 and 0.9.8a, only non-standard example ciphers where available, which cannot be used with any other clients. The same applies to ssl_stapling.t, but it also requires the certificate status TLS extension, which is only available since OpenSSL 0.9.8h, and therefore no additional checks are needed.