Passing pod UUID to Kubelet.

We need UUID to indicate the instance of a Pod to make restart work. 
Passing PodFullName to maintain the backward compatibility. Current support is you can passing name or name/uuid. 

Actually the current support is invoked through Kubelet's HTTP api: /proxy/minion/$host/run/$podname/<$uuid>/$containerName?cmd=...

If we decided to make sure name is required and unique in the space, I prefer to take podName only from HTTP request, then find the only running container which matches to podName, and call RunInContainer with uuid here.