Fixes issue with ThreadStatic db

Uses IScopeContext which wraps either HttpContext or CallContext which is created/injected via IOC factory.

src/Umbraco.Core/DependencyInjection/RepositoryCompositionRoot.cs

@@ -24,6 +24,8 @@ namespace Umbraco.Core.DependencyInjection
             container.Register<ISqlSyntaxProvider, SqlCeSyntaxProvider>("SqlCeSyntaxProvider");
             container.Register<ISqlSyntaxProvider, SqlServerSyntaxProvider>("SqlServerSyntaxProvider");
 
+            container.RegisterSingleton<IScopeContextFactory, DefaultScopeContextFactory>();
+
             // register database factory
             // will be initialized with syntax providers and a logger, and will try to configure
             // from the default connection string name, if possible, else will remain non-configured