Remove the gyp moving and symlinking

Per the comment this is supposed to fix PYTHONPATH issues but actually ends up making libexec/gyp.py the file that’s loaded when the script runs `import gyp` because it’s named gyp.py and in the same directory as the running script, see http://docs.python.org/2/tutorial/modules.html#the-module-search-path. `gyp.main` is looked up in the wrong file leading to errors of the form

```bash
Traceback (most recent call last):
  File "/opt/boxen/homebrew/bin/gyp", line 18, in <module>
    sys.exit(gyp.main(sys.argv[1:]))
AttributeError: 'module' object has no attribute 'main'
```

By not having the file named gyp.py ahead of the actual module in site-packages directory, `import gyp` loads the correct file