Pin testtools to 0.9.34 in test requirements
Pin testtools to 0.9.34 in test requirements

SubUnit is incompatible with newer testtools.

Closes-bug: 1274050
Change-Id: Ibe855930cecf6598ea72c13f609116450c719b46

junneyang/taskflow,varunarya10/taskflow,citrix-openstack-build/taskflow,pombredanne/taskflow-1,citrix-openstack-build/taskflow,openstack/taskflow,varunarya10/taskflow,jimbobhickville/taskflow,openstack/taskflow,jimbobhickville/taskflow,junneyang/taskflow,pombredanne/taskflow-1