test/functional/tests.py:TestObjectVersioningUTF8 does not clean
up the versions files it creates because the class's multiple
inheritance is such that it does not call the tearDown method in
TestObjectVersioning.
As a result, any attempt to clean up account containers wastes
time retrying container delete requests. This occurs either in
the setUp for TestSloEnv, if the TestSlo class is included in a
test run, or in the tests.py package tearDown method.
On the author's dev machine this patch reduces the execution
time of functional tests in tests.py by approx 30% or 1 minute.
Change-Id: I8194672bf2ca82435df5868720b6a55a79b94413
87fc21c7cf