Menu: fix incorrect default classes value

Author: arschmitz

tests/unit/menu/menu_common.js

@@ -1,7 +1,7 @@
 TestHelpers.commonWidgetTests( "menu", {
 	defaults: {
 		classes: {
-			"ui-menu": "ui-corner-all",
+			"ui-menu": "",
 			"ui-menu-icons": "",
 			"ui-menu-icon": "",
 			"ui-menu-item": "",

tests/unit/menu/menu_core.js

@@ -5,7 +5,7 @@ module( "menu: core" );
 test( "markup structure", function() {
 	expect( 6 );
 	var element = $( "#menu1" ).menu();
-	ok( element.is( ".ui-menu.ui-corner-all" ), "main element has proper classes" );
+	ok( element.hasClass( "ui-menu" ), "main element has proper classes" );
 	element.children().each(function( index ) {
 		ok( $( this ).hasClass( "ui-menu-item" ), "child " + index + " is .ui-menu-item" );
 	});

ui/menu.js

@@ -31,7 +31,7 @@ return $.widget( "ui.menu", {
 	delay: 300,
 	options: {
 		classes: {
-			"ui-menu": "ui-corner-all",
+			"ui-menu": "",
 			"ui-menu-icons": "",
 			"ui-menu-icon": "",
 			"ui-menu-item": "",