Update documentation regarding addition of SSL certificates.

[konobi]

We just debugged and fixed an issue in #smartos regarding adding real SSL certificates for a docker install, etc.

The documentation needs to be updated to take account of changes in the SSL ecosystem. Certificates are now being signed with extra additional intermediates to allow for more inter-CA trust, validation and revocation. We've seen this lots lately in relation to changing of certificates to support SHA256 and HPKP; Which are now part of PCI compliance testing.

The change is small, thankfully. Instead of using the certificate from the SSL vendor directly, the combination of the certificate and the ca bundle need to be concatenated together in the correct order and then the resultant chained certificate file used by the server as the certificate.

See the following for details: http://nginx.org/en/docs/http/configuring_https_servers.html#chains