rename options. (s/_/-/) according to Isaku Yamahata, this makes us look similar to openstack. caveat: no backward compat is provided. you need to update both of config files and cli options. Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>