x509: unhandled critical extension when pulling from internal registry

Issue

Cannot pull image from internal registry configured when pulls through external configured with custom cert. Or when environment is behind a proxy doing SSL decrypt/re-encrypt.

time="2019-11-18T02:43:00.837076273Z" level=error msg="response completed with error" err.code="openshift pullthrough manifest" err.message="unable to pull manifest from registry.redhat.io/xxxx/xxxx-yy-rhel7:latest: Get https://registry.redhat.io/v2/: tls: failed to parse certificate from server: x509: unhandled critical extension" go.version=go1.9.7 http.request.host="xxx.yyy.zzz.www:5000"