ccm: recognize InstanceNotFound from InstanceID

Otherwise we won't actually delete Nodes in this code path.

pkg/controller/cloud/node_controller.go

@@ -445,6 +445,9 @@ func ensureNodeExistsByProviderID(instances cloudprovider.Instances, node *v1.No
 		var err error
 		providerID, err = instances.InstanceID(context.TODO(), types.NodeName(node.Name))
 		if err != nil {
+			if err == cloudprovider.InstanceNotFound {
+				return false, nil
+			}
 			return false, err
 		}