Exit cleanly if run as a non-root user

Exits with a message if the efficitive-uid (EUID) is not 0

Change-Id: If36a9ede5f8bfc763d86870e6f630bafee605476
Reviewed-on: https://review.openstack.org/19453
Reviewed-by: Dan Prince <dprince@redhat.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Tested-by: Jenkins