Updated openstack/openstack
Project: openstack/oslo.i18n  ea7e0b3fd89480326df5cae8957b879330718fce

Activate pep8 check that _ is imported

Remove the specification in tox.ini that _ is a builtin so that
it will no longer assume that _ does not need to be imported.

This helps ensure that the _ from i18n is used.

Activating this check did not flag any violations.

Change-Id: I561e0dcf994768d5c7f7d88f595ebdf0c8dd118a