Adds cached_obj_get to put_detail and delete_detail methods

The new round of Authorization hooks do not work properly yet as the ModelResource does not populate the bundle.obj before doing the auth check. (This means you cannot check permissions against the instance in questions). 

All this patch adds is taking the cached_obj_get that was already being used for the get_detail method and applies it to the other detail methods (aside from create). It works and now the tests in my other pull request should pass.