Pass in the XHR object as the third argument to the success callback …

…(which helps $.get, $.post, and load). Fixes #3363.

src/ajax.js

@@ -469,7 +469,7 @@ jQuery.extend({
 		function success(){
 			// If a local callback was specified, fire it and pass it the data
 			if ( s.success ) {
-				s.success.call( callbackContext, data, status );
+				s.success.call( callbackContext, data, status, xhr );
 			}
 
 			// Fire the global callback