Revert "Avoid testtools 0.9.25"
Revert "Avoid testtools 0.9.25"

This reverts commit acae86293f7b0bba8fe105779f6f75df3af9ec51.
Testtools upstream is fixed.

Change-Id: Idc5f51bef76e31d627a80c742f5587d51e373d22

rajalokan/glance,stevelle/glance,redhat-openstack/glance,stevelle/glance,vuntz/glance,tanglei528/glance,darren-wang/gl,citrix-openstack-build/glance,klmitch/glance,akash1808/glance,rickerc/glance_audit,ntt-sic/glance,takeshineshiro/glance,darren-wang/gl,saeki-masaki/glance,openstack/glance,scripnichenko/glance,dims/glance,openstack/glance,SUSE-Cloud/glance,jumpstarter-io/glance,tanglei528/glance,akash1808/glance,paramite/glance,kfwang/Glance-OVA-OVF,saeki-masaki/glance,ntt-sic/glance,ozamiatin/glance,cloudbau/glance,SUSE-Cloud/glance,JioCloud/glance,redhat-openstack/glance,sigmavirus24/glance,wkoathp/glance,paramite/glance,dims/glance,scripnichenko/glance,takeshineshiro/glance,kfwang/Glance-OVA-OVF,openstack/glance,sigmavirus24/glance,klmitch/glance,ozamiatin/glance,citrix-openstack-build/glance,rickerc/glance_audit,wkoathp/glance,cloudbau/glance,vuntz/glance,rajalokan/glance,jumpstarter-io/glance,JioCloud/glance