Define a custom event prefix in the wpdialog jQuery UI widget to work around a jQuery UI 1.9.1 regression. see #22399.

git-svn-id: https://develop.svn.wordpress.org/trunk@22513 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/js/tinymce/plugins/wpdialogs/js/wpdialog.js

@@ -4,6 +4,7 @@
 		options: {
 			closeOnEscape: false
 		},
+		widgetEventPrefix: 'wpdialog',
 
 		open: function() {
 			var ed;