Functions Build/ParseDockerName now work with struct instead of the long
list of arguments. This new struct also was reused in the kubelet.go
instead of auxilary podContainer struct.
The policy today takes a min GC age, max dead containers per pod, and
max containers overall. When GC is called, only dead containers created
more than min GC age ago are considered. The policy tries to keep one
dead instance of every pod's containers.