In Python 3 __ne__ by default delegates to __eq__ and inverts the
result, but in Python 2 they urge you to define __ne__ when you define
__eq__ for it to work properly [1]. There are no implied relationships
among the comparison operators. The truth of x==y does not imply that
x!=y is false. Accordingly, when defining __eq__(), one should also
define __ne__() so that the operators will behave as expected.
[1]https://docs.python.org/2/reference/datamodel.html#object.__ne__
Change-Id: I9eb823d25d3b119653f31718056576dbc59b6960
In part of test refactoring, removing xml support form tacker/tests/unit
and tacker/api
Change-Id: Ia23564990fe6070c5f9163618688bfcab4dc87de
Partial-Bug: #1579167
howardlee