run_tests: strip locale archive to en_* locales
run_tests: strip locale archive to en_* locales

This is a workaround until https://review.openstack.org/#/c/304399/ will
be merged and a new image will be built and uploaded to OpenStack Infra
Clouds.

Until then, we'll carry this code so we can move forward with Puppet4
testing and deploy Facter correctly.

Change-Id: I823087aed543c3cf43d247f7adf5f32c5c0fc31e

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration