Make storage unmount less strict

There are cases where the container storage unmount has been already
(partially) done. This would cause `StopContainer()`  in
`server/container_stop.go:76` fail and therefore make containers get
stuck in recreation, making their pods stuck in `NotReady`.

We now double check the two c/stroage errors `ErrContainerUnknown` and
`ErrLayerUnknown`

Somehow related to:
containers/podman#11207 (comment)

Signed-off-by: Sascha Grunert <sgrunert@redhat.com>

internal/storage/runtime.go

@@ -460,11 +460,22 @@ func (r *runtimeService) StopContainer(ctx context.Context, idOrName string) err
 	if err != nil {
 		return err
 	}
-	_, err = r.storageImageServer.GetStore().Unmount(container.ID, false)
-	if err != nil {
-		log.Debugf(ctx, "Failed to unmount container %q: %v", container.ID, err)
-		return err
+
+	if _, err := r.storageImageServer.GetStore().Unmount(container.ID, true); err != nil {
+		if errors.Is(err, storage.ErrContainerUnknown) {
+			log.Infof(ctx, "Storage for container %s already removed", container.ID)
+			return nil
+		}
+
+		if errors.Is(err, storage.ErrLayerUnknown) {
+			log.Infof(ctx, "Layer for container %s not known", container.ID)
+			return nil
+		}
+
+		log.Warnf(ctx, "Failed to unmount container %q: %v", container.ID, err)
+		return fmt.Errorf("unmount storage: %w", err)
 	}
+
 	log.Debugf(ctx, "Unmounted container %q", container.ID)
 	return nil
 }