* Update Dockerfile

took out make -j 8 as we are running out of virtual memory.
added df -k for getting the disk space info in logs.

* Update .travis.yml

As we bring up 3 containers here i am reducing to 2 and trying to see if this is deployed on different  machines then should not matter.

* Update .travis.yml

3 in parallel should pass also 2 of then are passing so trying this out