Layer metadata storage has not been implemented outside of the layer store and will be deprecated by containerd metadata storage. To prepare for this and freeze the current metadata storage, remove the exported interface and make it internal to the layer store. Signed-off-by: Derek McGowan <derek@mcgstyle.net> Upstream-commit: 0aebcbc32dc6a7b35982a2bfc44335562cbb68ec Component: engine