The dependency on docker's filter package prevents us from using newer
versions of docker/moby where the package's API has changed. The filter
package is small enough to justify maintaining a small fork of it. Also,
since the opts package is only used for the `containers-storage` binary
and is not part of the actual storage library, move it to the ./internal
directory to make it clearer that this is an internal API.
Fixes: #450
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
Daniel J Walsh