In my case I have a `http_proxy` env variable on my development computer which passes all traffic to my vpn, however this proxy would fail to work when hostname is `localhost`, therefore when I'm testing my application it always fails because I setup my server at localhost, I want a method to force axios receiving a `none` for proxy config, currently if `proxy` property is `null` or `undefined` it will use the `http_proxy` env
test/unit/adapters/http.js
axios.get('http://localhost:4444/', {
        maxRedirects: 0,
        validateStatus: function () {
          return true;
        }
      }).then(function (res) {
        test.equal(res.status, 302);
        test.equal(res.headers['location'], '/foo');
        test.done();
      });
    });
  },
  testMaxRedirects: function (test) {
    var i = 1;
    server = http.createServer(function (req, res) {
      res.setHeader('Location', '/' + i);
      res.statusCode = 302;
      res.end();
      i++;
    }).listen(4444, function () {
      axios.get('http://localhost:4444/', {
        maxRedirects: 3
      }).catch(function (error) {
        test.done();
      });
    });
  },
  testTransparentGunzip: function (test) {
    var data = {
      firstName: 'Fred',