Fix closing admin menu animation. props filosofo, fixes #15615.

git-svn-id: http://svn.automattic.com/wordpress/trunk@16813 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/common.dev.js

@@ -47,8 +47,8 @@ adminMenu = {
 
 	toggle : function(el) {
 		var id = el.slideToggle(150, function() {
-			el.css('display','');
-		}).parent().toggleClass( 'wp-menu-open' ).attr('id');
+			el.parent().toggleClass( 'wp-menu-open' );
+		}).attr('id');
 
 		if ( id ) {
 			$('li.wp-has-submenu', '#adminmenu').each(function(i, e) {