tests: Add MTU test for swarm
tests: Add MTU test for swarm

Check MTU interfaces and values using swarm.

Fixes #688

Signed-off-by: Gabriela Cervantes <7478955d4356a4dc893d64d1345a99c9f58c91ab@intel.com>

chavafg/tests,clearcontainers/tests,devimc/tests,MarioCarrilloA/tests,devimc/tests,chavafg/tests,clearcontainers/tests,MarioCarrilloA/tests