Fix "keyword argument repeated" error when running setup.py.

[synthead]

This commit fixes the "keyword argument repeated" error when running setup.py:

  File "setup.py", line 45
    include_dirs=["WiringPi/wiringPi"],
       ^
SyntaxError: keyword argument repeated

I simply removed the offending line as include_dirs=['WiringPi/wiringPi','WiringPi/devLib'], was already in the _wiringpi2 object. My guess is that this was broken in a merge somewhere.