Pin testtools to < 0.9.36
Pin testtools to < 0.9.36

New testtools require that setUp() and tearDown() are not called twice,
while test_schema is built around multiple calls. So pinning the version
for now until a proper fix is implemented.

Closes-Bug: 1360252
Change-Id: I184db35242d036dacc7933c1d762cccc7f5c40bb

openstack/sqlalchemy-migrate,andras-tim/sqlalchemy-migrate,rcherrueau/sqlalchemy-migrate,rcherrueau/sqlalchemy-migrate,stackforge/sqlalchemy-migrate,dannon/sqlalchemy-migrate,openstack/sqlalchemy-migrate