Add CA roots for upcoming rubygems.org cert change

We need to deploy a new server certificate as Google Chrome no longer
trusting SHA-1-signed certificates:

  http://blog.chromium.org/2014/09/gradually-sunsetting-sha-1.html

In order to avoid interruption of service users will need the updated
root certificates to verify the new server certificate.  Users may be
able to install these certificates by hand into their OpenSSL
certificates pem as well.
Update release date and version