Updating security processing. Adding a base for an OrchardException hierarchy.

--HG--
extra : convert_revision : svn%3A5ff7c347-ad56-4c35-b696-ccb81de16e03/trunk%4045830

src/Orchard.Web/Packages/Orchard.Roles/Controllers/AdminController.cs

@@ -111,7 +111,7 @@ namespace Orchard.Roles.Controllers {
             var simulation = UserSimulation.Create(role.Name);
             model.EffectivePermissions = model.PackagePermissions
                 .SelectMany(group => group.Value)
-                .Where(permission => _authorizationService.CheckAccess(simulation, permission))
+                .Where(permission => _authorizationService.TryCheckAccess(simulation, permission))
                 .Select(permission=>permission.Name)
                 .Distinct()
                 .ToList();