Right now 'docker build' will send: Sending build context to Docker daemon to stderr, instead of stdout. This PR fixes that. I looked in the rest of api/client/commands.go for other cases that might do this and only one jumped out at me: https://github.com/docker/docker/blob/master/api/client/commands.go#L2202 but I think if I changed that to go to stdout then it'll mess people up who are expecting just the container ID to be printed to the screen and there is no --quiet type of flag we can check. Closes #9404 Signed-off-by: Doug Davis <dug@us.ibm.com> Upstream-commit: 5c91bb93a7e35b2d443090cabc7ec0a2ca59b6ee Component: engine