Patch to origin/commit-change patch to add docker import support

    pass --change changes to the import job

    Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)

I have added a patch to  https://github.com/docker/docker/pull/8765

Which implements docker import --change.
can we change this text - its confusing me

something more like
`Run a Dockerfile instruction before commiting the image`

another thing that i'm curious about - does the instruction run in the container, and so will persist if i `docker start` it again, or is the container commited, then a new one made based on that image, and the instruciton run in that temporary container..

we should probably mention which ever that is in the docs too.