The only external consumer are the `graphdriver` and `graphdriver/shim`
packages in github.com/docker/go-plugins-helpers, which depended on
[ContainerFS][1], which was removed in 9ce2b30b81.
graphdriver-plugins were deprecated in 6da604aa6a,
and support for them removed in 555dac5e14,
so removing this should not be an issue.
Ideally this package would've been moved inside `daemon/internal`, but it's used
by the `daemon` (cleanupContainer), `plugin` package, and by `graphdrivers`,
so needs to be in the top-level `internal/` package.
[1]: 6eecb7beb6/graphdriver/api.go (L218)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
