avoid using relative path in fb_py_win_main
avoid using relative path in fb_py_win_main

Summary:
After some experimenting, it is a little awkward if we want to specify a relative path based on the executable location. We'd need to add a bunch of path calculations to make it right, and I don't think the added complexity is really worth the effort.

As a result, let's just remove the use of relative path, and if we ever want to ship a copy of Python distribution, we can place it under the same directory as the binary.

Reviewed By: chadaustin

Differential Revision: D22394180

fbshipit-source-id: 86d27f6d16a03fe08826b5e5eafcef2a1c77997f

rsocket/rsocket-cpp,rsocket/rsocket-cpp,ReactiveSocket/reactivesocket-cpp,ReactiveSocket/reactivesocket-cpp,rsocket/rsocket-cpp,rsocket/rsocket-cpp,ReactiveSocket/reactivesocket-cpp