I have axios@0.15.2

If this HTML is run, some requests will be cancelled by Chrome:

    <html>
    <head>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/axios/0.15.2/axios.js"></script>
    </head>
        <script>
        var promises = [];
        window.onload = function() {
            for (var i = 0; i < 4; i++) {
                var promise = axios.get('some url which causes ERR_CONNECTION_CLOSED');
                promises.push(promise);
            }
        }
       </script>
    </html>

![Cancelled](https://cloud.githubusercontent.com/assets/4506837/20349972/9123cef0-ac2e-11e6-93db-0ec66f205382.png)

But promises which turned into cancelled request won't be fulfilled:

![notfulfilled](https://cloud.githubusercontent.com/assets/4506837/20350023/d2146c4e-ac2e-11e6-89bc-983233628d09.png)

test/specs/requests.spec.js
headers: {
        'Accept': 'application/json'
      }
    })
    .catch(function (error) {
      response = error.response;
    });
    getAjaxRequest().then(function (request) {
      request.respondWith({
        status: 400,
        statusText: 'Bad Request',
        responseText: '{"error": "BAD USERNAME", "code": 1}'
      });
      setTimeout(function () {
        expect(typeof response.data).toEqual('object');
        expect(response.data.error).toEqual('BAD USERNAME');
        expect(response.data.code).toEqual(1);
        done();
      }, 100);
    });
  });
  it('should make cross domian http request', function (done) {
    var response;
    axios.post('www.someurl.com/foo').then(function(res){
      response = res;
    });
    getAjaxRequest().then(function (request) {
      request.respondWith({
        status: 200,
        statusText: 'OK',