Passing pod UUID to Kubelet.

We need UUID to indicate the instance of a Pod to make restart work. 
I thought about it before, but had some concerns on it. Currently hasContainer hashes Container's config, and every sync loop, kubelet compares the hash_values to see if container config changed. If I embedded both UUID and container config into one hash object, I can tell it is a new UUID for a newly created Pod, or a container changes? Please note that kubelet doesn't have persistent states yet. I plan to add some soon, but not now. 

If you think UUID is too long for a docker container, I can hash it separately.