[TIMOB-17062] iOS: onload callback is not triggered second time for existing HTTPClient object

var win = Ti.UI.createWindow({backgroundColor:'white'});
var button = Ti.UI.createButton({
	title:'load',
	top:'20%',
	bottom:'20%',
	left:'20%',
	right:'20%'
	});

win.add( button );

var xhr;	
button.addEventListener('click', function () {
	button.title = 'parsing...';
	if(!xhr){
		xhr = Titanium.Network.createHTTPClient({onload: function() {
			Ti.API.info('onload');
			button.title = 'load';	
		}});
	}
	
    //Abort existing call
    xhr.abort();
	
    // open the client
    xhr.open('GET', 'http://www.tfl.gov.uk/tfl/syndication/feeds/cycle-hire/livecyclehireupdates.xml');
    xhr.send();
});

win.open();