Cleans up the create_conf tool
Cleans up the create_conf tool

 * Makes it adhere to the config file format
 * Puts the sample output in etc/nova/nova.conf.sample
 * Updating sample is as easy as ./tools/conf/generate_sample.sh

Change-Id: I01e72cb58dd598a74f50c2c17f102d24df325f2e

n0ano/gantt,n0ano/gantt