return error when got error from LoadFromUrl instead of exiting

kubedd/kubedd.go

@@ -91,7 +91,7 @@ func ValidateCluster(cluster *pkg.Cluster, conf *pkg.Config) ([]pkg.ValidationRe
 		err := kubeC.LoadFromUrl(conf.TargetKubernetesVersion, false)
 		if err != nil {
 			kLog.Error(err)
-			os.Exit(1)
+			return make([]pkg.ValidationResult, 0), err
 		}
 	}
 	serverVersion, err := cluster.ServerVersion()