win,openssl: disable some warnings

This patch disables two (categories of) warnings:

  * deprecation of GetVersionExA
  * possible loss of data in implicit conversion of scalar types

These warnings don't seem to point out serious problems, and avoiding
them in openssl is somebody else's business.

PR-URL: https://github.com/iojs/io.js/pull/261


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>