When ID of missing product is passed, then warning is raised during permission checking

For all category items (except of products) when ID of missing item is given, then "404 Not Found" page is shown. Don't know why this behavior is disabled for products, but because of that additional warning during permission checking is raised.

How to reproduce:

1. Go to product detail page of any product (mod-rewrite mode should be disabled).
2. Replace ID of product to any ID, that doesn't match to any available product (DBG_REDIRECT should be turned on).
3. See warning in kPermissionHelper class (in debugger).