Changing deprecated library reference and setting delete propagation background policy (#5161)

Signed-off-by: Amim Knabben <amim.knabben@gmail.com>

cmd/helm/installer/uninstall.go

@@ -47,10 +47,11 @@ func deleteService(client corev1.ServicesGetter, namespace string) error {
 }
 
 // deleteDeployment deletes the Tiller Deployment resource
-// We need to use the reaper instead of the kube API because GC for deployment dependents
-// is not yet supported at the k8s server level (<= 1.5)
 func deleteDeployment(client kubernetes.Interface, namespace string) error {
-	err := client.Extensions().Deployments(namespace).Delete(deploymentName, &metav1.DeleteOptions{})
+	policy := metav1.DeletePropagationBackground
+	err := client.AppsV1().Deployments(namespace).Delete(deploymentName, &metav1.DeleteOptions{
+		PropagationPolicy: &policy,
+	})
 	return ingoreNotFound(err)
 }