[oe] [meta-python][PATCH v2] Add some python packages bb

[mingli.yu at windriver.com]

1, Add python-pbr bb file as python-mock depends on
   python-pbr-native

2, Update python-mock bb to add python-pbr-native dependency 
   for python-mock

3, Update python-mccabe bb to add python-pytest-runner 
   dependency for python-mccabe

4, Add python-pytest-runner bb as python-mccabe depends
   on python-pytest-runner

5, Add python-setuptools-scm bb as python-pytest-runner depends
   on python-setuptools-scm