Deleting a device does not discard the device from storage

When a delete operation is performed on a disabled device, the device does not get discarded from the kv storage.  It seems like the model is unaware of the exact location of the device in the KV store. 

-We need to properly carry that location information from one revision to another. 

-We also need to make sure that the watch operation does not detect a change at that location and try to store back the information