Updates controller node under basic_install_guides

Updates the controller node with the following changes:

 Fixes network interfaces file's comments
 Changes ubuntu version from 12.04 to 14.04
 Other minor updates like fixing typos etc.

Change-Id: Iddb2b75a1b119d93b9479d0c8791f21966d2ee5b
Merge "Updates controller node under basic_install_guides"