Automatic merge from submit-queue
getting emailAddress from TLS cert
Kubernetes if using TLS cert to perform authentication will use the CommonName field of the cert as the authenticating user. In https://github.com/kubernetes/kubernetes/blob/master/plugin/pkg/auth/authenticator/request/x509/x509.go#L106, alternative methods are defined to use emailAddress or DNSName as the authenticating user. The method that uses the emailAddress is not comprehensive as this information can be encoded in different places of the certificate. This PR fixes this.
There are quite a few 'composite literal uses unkeyed fields' errors that I have kept out of this patch.
And there's a couple where vet just seems confused. These are the easiest ones.