Use testtools for better Python 2.6 compatibility
Use testtools for better Python 2.6 compatibility

Testsuite uses assertDictEqual and a few others
which do not exist for Python 2.6. Use testtools
for those instead, which works the same for
all Python versions.

Change-Id: I7c6cba7c032a721f2ade0055066b9ddfac6a35c9

bbandaru/heat-cfntools,openstack/heat-cfntools