Replace assertEquals with assertEqual
Replace assertEquals with assertEqual

The method assertEquals has been deprecated since python 2.7.
http://docs.python.org/2/library/unittest.html#deprecated-aliases

Also in Python 3, a deprecated warning is raised when using assertEquals
therefore we should use assertEqual instead.

This is part of blueprint assertequal

Change-Id: Ie6b881f594c0b3e7015e70a12d7ac720fa765736

openstack/swift-bench,openstack/swift-bench