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
python-openstackclient/locale/python-openstackclient.pot to
openstackclient/locale/openstackclient.pot. For this we need to update
setup.cfg.
Update also domain name in i18n.py.
Change-Id: I89fad12f20775c8b7cd228348ff82a77488e6ab2