Pin testtools to avoid breakage in 0.9.35
Pin testtools to avoid breakage in 0.9.35

Change-Id: I33a81f8aac790626f77a9c3fd5419e6fc8179b6a
Signed-off-by: Paul Belanger <b4265d8fef626f73eff739ef4ffce9d45b30eddd@polybeacon.com>

kickstandproject/python-ari