Fix ConfigParser import for Python3 in setup_posix.py

[larsbutler]

Otherwise, this module will raise ModuleNotFound errors on import.

I found out about this issue from a comment in a Stackoverflow thread: https://stackoverflow.com/questions/35641893/best-way-for-python-to-interface-with-mysql/35842375?noredirect=1#comment84048239_35842375.

[hugovk]

These are duplicates: #59, #126, #136, #138.

A fix is also included in #62.