Ran into this problem today with Swift, spent an hour working through this python version issue. I use a number of packages under "port" that installed python along the way. Can't uninstall python without uninstalling the other stuff.
I found an easy solution:
* Get the "six" package from here: https://pypi.python.org/pypi/six/
* Unpack it
* Copy six.py to /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
I don't directly use python, so this may have unintended consequences if you move between 2.7 and 3.5, but it did fix my Swift startup problem.