systemtest: copy: docker->storage->oci-archive
systemtest: copy: docker->storage->oci-archive

Add a systemtest copying an image from docker to storage and then to an
oci-archive.  There are other ways to trigger the same code paths, but
this one has caught a regression in c/image in libpod's.

Fixes: #734
Signed-off-by: Valentin Rothberg <c8d7c67387706f1534261b1aba83f5c355c00ff5@redhat.com>

mtrmac/skopeo,mtrmac/skopeo,mtrmac/skopeo