Update jquery.ui.widget.js

Cross-Browser Error : on $.each for jquery
existingConstructor._childConstructors doesn't have length method
( widget call by progressbar plugin ).

Uncaught TypeError: Cannot read property 'length' of undefined jquery-1.7.2.min.js:2
e.extend.each jquery-1.7.2.min.js:2
$.widget jquery.ui.widget.js:122
(anonymous function) jquery.ui.progressbar.js:17
(anonymous function) jquery.ui.progressbar.js:145