add DockerPorts to cluster config

pkg/minikube/config/types.go

@@ -71,6 +71,7 @@ type ClusterConfig struct {
 	Addons                  map[string]bool
 	VerifyComponents        map[string]bool // map of components to verify and wait for after start.
 	StartHostTimeout        time.Duration
+	DockerPorts             []string // Only used by the docker driver
 }
 
 // KubernetesConfig contains the parameters used to configure the VM Kubernetes.