Workaround of subunit when setup is git
Workaround of subunit when setup is git

A former patch applied the following patch
https://github.com/testing-cabal/subunit/pull/36.
This patch add a condition to apply it only when running tempest from
git. When running tempest from RPM subunit is taken from os-testr
instead of from pip

Change-Id: I31cafff2d78f0bad9ddb02d36cbb71c12427801d

redhat-openstack/infrared,redhat-openstack/infrared,redhat-openstack/infrared