The call to io.Copy was not being checked for errors at a critical point in the pull logic. This patch will log the error value if not nil. Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn) Upstream-commit: 6564e0ad2f63257458a5bad68f47504223b00285 Component: engine