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: I928c8fecfe17029ba7b60135fa2c2d94db447099

openstack/openstack-ansible-openstack_hosts,openstack/openstack-ansible-openstack_hosts