Pin test-requirements to match OpenStack requirements
Pin test-requirements to match OpenStack requirements

A new release of flake8 is causing lint faiures. Our requirements
should match OpenStack requirements anyway.

This patch pins to the current master requirements from the
OpenStack requirements repository using global-requirements.

Change-Id: If99c8d22742b5540073368e57ad241d87fc74404

openstack/openstack-ansible-galera_server,os-cloud/openstack-ansible-galera_server,os-cloud/openstack-ansible-galera_server,openstack/openstack-ansible-galera_server