I could not update a product with the old code.  This fixed it.
But to be honest, I forgot about this.   Maybe some of the parameters are needed?  I didn't really test it out.  Can you tell me, or do I test it out?

For instance, if you use activeresource to make client classes, you'll see a lot of attributes get added. 
If you try to save then, it fails because of these attributes that are not allowed to be posted (mass assignment ...).