AssertEquals() logs a DeprecationWarning in Python 3.x, use assertEqual() instead

[jingtao liang]

Follow the http://docs.openstack.org/developer/hacking/:
assertEquals() logs a DeprecationWarning in Python 3.x, use assertEqual() instead.
The same goes for assertNotEquals().But Stevedore still have the problem.Let's fix
it.

[ChangBo Guo(gcb) (glongwave)]

Fix in https://review.openstack.org/#/c/340296/

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/stevedore 1.17.0 release.

[C.W.Holeman II (cwhii)]

This is the wrong Stevedore, there is no Python here.