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
networking-l2gw/locale/networking-l2gw.pot to
networking_l2gw/locale/networking_l2gw.pot. For this we need to update
setup.cfg.
Update also domain name in _i18n.py.
Let's remove the po and pot files in the outdated paths.
The updated scripts work without them. So, we can just
delete the files and once the infra script runs,
an updated pot file together with translations
will be imported automatically.
Change-Id: I5e2db2ff767c25db9bb62aac8b826ba557393a5f