Fake clientset no longer needs to be prepopulated with records: keeping
them in leads to the name conflict on creates. Also, since fake
clientset now respects namespaces, we need to correctly populate them.
Automatic merge from submit-queue
update controllers watching all pods to share an informer
This plumbs the shared pod informer through the various controllers to avoid duplicated watches.
A lot of packages use StringSet, but they don't use anything else from
the util package. Moving StringSet into another package will shrink
their dependency trees significantly.
