Update c/image for https://github.com/containers/image/pull/912

This is an unreleased version of c/image, but it is important to
to have the test added in in the next commit enforcing as soon as
possible.

> go get github.com/containers/image/v5@HEAD
> make vendor

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/github.com/containers/storage/layers.go

@@ -992,6 +992,9 @@ func (r *layerStore) deleteInternal(id string) error {
 	if err == nil {
 		os.Remove(r.tspath(id))
 		delete(r.byid, id)
+		for _, name := range layer.Names {
+			delete(r.byname, name)
+		}
 		r.idindex.Delete(id)
 		mountLabel := layer.MountLabel
 		if layer.MountPoint != "" {