config: Add docker_swarm_version
config: Add docker_swarm_version

Docker swarm requires an older version of docker currently.

Partially fixes #781.

Signed-off-by: James O. D. Hunt <348fbaadfbada55ea105602bf5609e23ac1c4898@intel.com>

clearcontainers/runtime,devimc/runtime,chavafg/runtime,clearcontainers/runtime,chavafg/runtime,devimc/runtime