Async calls cause InvalidStateError in IE 11

[jakubukrop]

HttpProvider.sendAsync() causes InvalidStateError in IE 11

It seems that IE has a problem when request.timeout is set before request.open().
See lib/web3/httpprovider.js:

HttpProvider.prototype.prepareRequest = function(async) {
    var request;

    if (async) {
        request = new XHR2();
        request.timeout = this.timeout; // <-- IE11 needs this after request.open()
    } else {
        request = new XMLHttpRequest();
    }
    request.open('POST', this.host, async);

Note: The same issue has been reported in other projects: stephanebachelier/superapi#5
and airbrake/airbrake-js#302

[nivida]

This got fixed here: 0207369.