Python interface module depends on google-common which is not used

Currently the Python interface module explicitly depends on google-common, see src/python/interface/setup.py.in

    'install_requires': [ 'google-common>=0.0.1', 'protobuf>=3.3.0,<4' ],

This was added in b426d5adca as a workaround, https://reviews.apache.org/r/37081/#comment148768.

We should clean up the dependencies here to make sure we only introduce dependencies we require ourself.