This introduces Versions for TarSum checksums.
Fixes: https://github.com/docker/docker/issues/7526
It preserves current functionality and abstracts the interface for
future flexibility of hashing algorithms. As a POC, the VersionDev
Tarsum does not include the mtime in the checksum calculation, and would
solve https://github.com/docker/docker/issues/7387 though this is not a
settled Version is subject to change until a version number is assigned.
Signed-off-by: Vincent Batts <vbatts@redhat.com>
Upstream-commit: 747f89cd327db9d50251b17797c4d825162226d0
Component: engine
