Use alternative workaround for cafile issue with node v4

[springmeyer]

I think we can remove https://github.com/mapbox/ci-scripts/blob/master/node/ci-cpp.bat#L38-L46. This is because I found that this problem can be worked around by upgrading node-gyp. See mapbox/node-pre-gyp#209 (comment)

@BergWerkGIS can you please:

• Confirm that upgrading node-gyp (which should already be being done in the package.json) works around this problem in the repos you've been testing?
• If so we'll plan to keep node-gyp upgrade in place for node v4 (and not just for node v0.10.x), and this should be documented in the readme for co-scripts

[wilhelmberg]

Removed cafile workaround: 47726e2

Confirm that upgrading node-gyp (which should already be being done in the package.json) works around this problem in the repos you've been testing?

All repositories I've been testing are ✅ on AppVeyor (node-gdal still running as of now).

If so we'll plan to keep node-gyp upgrade in place for node v4 (and not just for node v0.10.x), and this should be documented in the readme for co-scripts

done: https://github.com/mapbox/ci-scripts/tree/master/node