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
lastName: 'Flintstone',
      emailAddr: 'fred@example.com'
    };
    zlib.gzip(JSON.stringify(data), function(err, zipped) {
      server = http.createServer(function (req, res) {
        res.setHeader('Content-Type', 'application/json;charset=utf-8');
        res.setHeader('Content-Encoding', 'gzip');
        res.end(zipped);
      }).listen(4444, function () {
        axios.get('http://localhost:4444/').then(function (res) {
          test.deepEqual(res.data, data);
          test.done();
        });
      });
    });
  },
  testGunzipErrorHandling: function (test) {
    server = http.createServer(function (req, res) {
      res.setHeader('Content-Type', 'application/json;charset=utf-8');
      res.setHeader('Content-Encoding', 'gzip');
      res.end('invalid response');
    }).listen(4444, function () {
      axios.get('http://localhost:4444/').catch(function (error) {
        test.done();
      });
    });
  },
  testUTF8: function (test) {
    var str = Array(100000).join('ж');
    server = http.createServer(function (req, res) {