tox: stop validating locale files
tox: stop validating locale files

They are autogenerated, and the updates are submitted automatically.
There is no much value in validating them. Also the recent translation
update https://review.openstack.org/#/c/542609/ removes the last pot
file and this validation starts failing.

Change-Id: I08a5c6acf4312df307aee4ba66f3d957191c8708

openstack/ironic,openstack/ironic