Accordion: Fixed back-compat for icons.headerSelected when icons option is null.

Author: scottgonzalez

demos/accordion/custom-icons.html

@@ -20,7 +20,7 @@
 			icons: icons
 		});
 		$( "#toggle" ).button().toggle(function() {
-			$( "#accordion" ).accordion( "option", "icons", false );
+			$( "#accordion" ).accordion( "option", "icons", null );
 		}, function() {
 			$( "#accordion" ).accordion( "option", "icons", icons );
 		});

ui/jquery.ui.accordion.js

@@ -628,8 +628,10 @@ if ( $.uiBackCompat !== false ) {
 
 		var _createIcons = prototype._createIcons;
 		prototype._createIcons = function() {
-			this.options.icons.activeHeader = this.options.icons.activeHeader ||
-				this.options.icons.headerSelected;
+			if ( this.options.icons ) {
+				this.options.icons.activeHeader = this.options.icons.activeHeader ||
+					this.options.icons.headerSelected;
+			}
 			_createIcons.call( this );
 		};
 	}( jQuery, jQuery.ui.accordion.prototype ) );