RequestBuilder::build creates a url with extra '& at the end

[hmacias-avaya]

When doing something like

let url = "http://something.com/get?param1=value1";
let request = Request::get(url).build().unwrap();

the request created will target http://something.com/get?param1=value1& and not the original url, http://something.com/get?param1=value1 (note there is an '&' added).

I'm providing a test and the fix for it.
Sorry I couldn't figure out how to put the test where it should be going (somewhere in http?)