openstack copyright notice

restore openstack copyright notice for the code taken from them.

> commit f2c6dfe1066aeecb5fdf2fb1cd5ce6476565fd24
> Author: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> Date:   Fri Nov 30 15:54:12 2012 +0900
>
>     set setup.py install_requires properly
>
>     Let's enable pip to solve the dependency.
>
>     The code is taken from OpenStack.
>
>     Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>