subtests.docker_cli: Add test run_cidfile

Fixes: https://github.com/autotest/autotest-docker/issues/264

This test is focussed on correct handling of `docker run --cidfile`

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
I agree, they're already talking about a Docker 2.0 with format changes *and* backward compatibility, so I don't see it as a problem that will go away for a long while.  We probably need an entire module dedicated for this purpose :sweat: