cinder: drop python-oauth2client dependency in favor of python-googleauth (same purpose but newer and maintained), thanks @tsimonq2 for sponsoring
python-googleapi: also drop python-oauth2client for python-googleauth, again thanks @tsimonq2 for sponsoring
discussions around removing pydrive which also depends on python-oauth2client and has been replaced with pydrive2 (which also uses python-oauth2client however) but I still need to open a bug about its removal