Updated conf.sample files with user/chef info

* 'user' option identifies the default username to be used with the
image.
* 'chef_server_ip' and 'chef_server_hostname' is to identify the
chef-server.

Signed-off-by: Shashank Sahni <shredder12@gmail.com>
Added function to setup chef hostname resolution

* Added setup_chefserver_hostanme() in configure.py to enable
  hostname resolution in all instances. It adds a static entry in
  /etc/hosts.
* Updated cluster.create and scheduler.schedule() to pass required
  parameters for the same.

Signed-off-by: Shashank Sahni <shredder12@gmail.com>
Fixed cloud conf identification part in config.py

This function splits the filename and checks whether the extension is
'conf'. Updated the extension fetching function to check the last
element by spliting the filename instead of the second.

Signed-off-by: Shashank Sahni <shredder12@gmail.com>