fix: pin mock to 1.0.1

- pinning mock to 1.0.1 under tests/test-requirements.txt did not work,
  probably because some other framework has a dependency on it, putting
  it in the last line did not work either.

Change-Id: I67fd7d170fb653f18bb5b90fbffab202b7c2bc67

tox.ini

@@ -17,7 +17,8 @@ setenv = VIRTUAL_ENV={envdir}
          PYTHONDONTWRITEBYTECODE=1
 deps = -r{toxinidir}/requirements/requirements.txt
        -r{toxinidir}/tests/test-requirements.txt
-commands = pip install git+https://github.com/stackforge/opencafe.git#egg=cafe
+commands = pip install -U mock==1.0.1
+           pip install git+https://github.com/stackforge/opencafe.git#egg=cafe
            nosetests {posargs:--exclude=api --exclude=endtoend --nologcapture}