The test was failing because TarOptions was using a non-pointer for
ChownOpts, which meant the check for nil was never true, and
createTarFile was never using the hdr.UID/GID
Signed-off-by: Daniel Nephin <dnephin@docker.com>
This changes the long-standing bug of copy operations not preserving the
UID/GID information after the files arrive to the container.
Signed-off-by: Erik Hollensbe <github@hollensbe.org>