Removing restriction that site-packages have `pythonX.Y` in path.
Removing restriction that site-packages have `pythonX.Y` in path.

See (e.g.):
https://ci.appveyor.com/project/dhermes/bezier/build/1.0.397.master/job/tdx5dkb37f8vwh0u

Where the path ends in

    lib\site-packages\bezier\include

rather than

    lib\python2.7\site-packages\bezier\include

dhermes/bezier,dhermes/bezier,dhermes/bezier