Move UmbracoConfig singleton to Current

src/Umbraco.Web/Install/InstallSteps/NewInstallStep.cs

@@ -8,6 +8,7 @@ using System.Web;
 using System.Web.Security;
 using Newtonsoft.Json;
 using Umbraco.Core;
+using Umbraco.Core.Composing;
 using Umbraco.Core.Configuration;
 using Umbraco.Core.Migrations.Install;
 using Umbraco.Core.Services;
@@ -82,7 +83,7 @@ namespace Umbraco.Web.Install.InstallSteps
             admin.Username = user.Email.Trim();
 
             _userService.Save(admin);
-            
+
             if (user.SubscribeToNewsLetter)
             {
                 if (_httpClient == null)
@@ -144,7 +145,7 @@ namespace Umbraco.Web.Install.InstallSteps
 
             // In this one case when it's a brand new install and nothing has been configured, make sure the
             // back office cookie is cleared so there's no old cookies lying around causing problems
-            _http.ExpireCookie(UmbracoConfig.For.UmbracoSettings().Security.AuthCookieName);
+            _http.ExpireCookie(Current.Config.Umbraco().Security.AuthCookieName);
 
                 return true;
         }