Follow new infra setup for translations, see spec
http://specs.openstack.org/openstack-infra/infra-specs/specs/translation_setup.html
for full details.
This basically renames
oslo.concurrency/locale/oslo.concurrency.pot to
oslo_concurrency/locale/oslo_concurrency.pot. For this we need to update
setup.cfg.
Update also domain name in i18n.py.
Change-Id: Ie774c4252f8481f2541ed0a2cad565d149dfcc72