docker driver: propagate NeedsImprovement and Fix to the caller
docker driver: propagate NeedsImprovement and Fix to the caller

Signed-off-by: Akihiro Suda <10ddef0dea2a66ab193b07198faa879adcb213d8@hco.ntt.co.jp>

warmchang/minikube,warmchang/minikube,kubernetes/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,kubernetes/minikube,kubernetes/minikube,warmchang/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube,kubernetes/minikube,warmchang/minikube