This changes ExportChanges to use the go tar support so we can
directly create tar layer files. This has several advantages:
* We don't have to create the whiteout files on disk to get them
added to the layer
* We can later guarantee specific features (such as xattrs) being
supported by the tar implementation.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: d54ce8087aba23663856c81a3fb5475979bdf453
Component: engine