Net demo installer script

[dvavili]

Installer script to install necessary services for trying out contiv networking. Following are the checks and steps done by the instaaler script:

• check to see if the right version of OS is installed on all the nodes and if connection can be established
• provision the nodes via ansible which installs the necessary base packages starts necessary services like etcd, swarm, netmaster, netplugin.

[dvavili]

Incorporated the changes