
The admin kubeconfigs we have on EKS clusters are a bit different from others, because there is no certificate/key (EKS does not use certificate auth). This code didn't quite work correctly in that case. The fix is to allow the case where `tlsConfig.GetClientCertificate` is non-nil, but returns a value with no certificates. Signed-off-by: Matt Moyer <moyerm@vmware.com>