This makes `--cidfile` clean up empty container ID files. These are
left behind when creating the container fails.
Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Upstream-commit: a56d1b93a1a16ac482b5e30773664f2538949c53
Component: engine