mw/kubernetes: revert if-else for health (#970)

Do the return early and dedent the rest of the function.

middleware/kubernetes/kubernetes.go

@@ -154,7 +154,15 @@ func (k *Kubernetes) getClientConfig() (*rest.Config, error) {
 	overrides := &clientcmd.ConfigOverrides{}
 	clusterinfo := clientcmdapi.Cluster{}
 	authinfo := clientcmdapi.AuthInfo{}
-	if len(k.APIServerList) > 0 {
+
+	if len(k.APIServerList) == 0 {
+		cc, err := rest.InClusterConfig()
+		if err != nil {
+			return nil, err
+		}
+		return cc, err
+	}
+
 	endpoint := k.APIServerList[0]
 	if len(k.APIServerList) > 1 {
 		// Use a random port for api proxy, will get the value later through listener.Addr()
@@ -210,13 +218,7 @@ func (k *Kubernetes) getClientConfig() (*rest.Config, error) {
 		endpoint = fmt.Sprintf("http://%s", listener.Addr())
 	}
 	clusterinfo.Server = endpoint
-	} else {
-		cc, err := rest.InClusterConfig()
-		if err != nil {
-			return nil, err
-		}
-		return cc, err
-	}
+
 	if len(k.APICertAuth) > 0 {
 		clusterinfo.CertificateAuthority = k.APICertAuth
 	}