RFR: 8227642: [TESTBUG] Make docker tests podman compatible

[Igor Ignatyev]

> On Jul 18, 2019, at 8:14 AM, Severin Gehwolf <sgehwolf at redhat.com> wrote:
> 
>> should we rename docker.support and DOCKER_COMMAND to something more abstract?
> 
> container.support and CONTAINER_ENGINE_COMMAND perhaps?

sounds good to me, but as Misha suggested (and I originally intended to write), let's do this renaming in a separate RFE. that's to say, you can consider 8227642 as fully reviewed.

Thanks,
-- Igor