The mock module has been added to Python 3.3 as unittest.mock.
The third party mock module doesn't seem to be maintained anymore: the
last commit was in April 2013.
unittest.mock is more recent, has less bugs and is compatible with
Python 3.4. There are bugs on Python 3 in the third party mock module,
examples:
* https://code.google.com/p/mock/issues/detail?id=225
* https://code.google.com/p/mock/issues/detail?id=234
Oslo Messaging hits these issues when running tests on Python 3.4.
Import oslotest to setup six.moves for mock.
Change-Id: Ic160101695cea67eb9bbbfcaddb8d3dac64e6804