npc: Track ipset entries per user

There was a bug in handling "default-allow" ipsets - it could not
cope with out of order receive of Pod updates. E.g:

    1) AddPod(Pod_A, PodIP_A),
    2) AddPod(Pod_B, PodIP_A),
    3) DeletePod(Pod_A),

would result with PodIP_A being removed from "default-allow" ipset,
as such ipset entries were not refcounted. Bypassing of refcounting
was due to the fact that adding a netpol which dst-selects a Pod which
IP addr is in "default-allow" ipset has to remove the IP addr from
the ipset regardless of refcount value of the IP addr entry in the
ipset. So, refcounting in such case didn't make sense and it was
bypassed.

This commit changes the way entries are refcounted in ipsets, and
it makes "default-allow" ipset the same citizen as other ipsets, so
from now "default-allow" ipset is refcounted.

npc/controller.go

@@ -59,7 +59,7 @@ func (npc *controller) onNewNsSelector(selector *selector) error {
 	for _, ns := range npc.nss {
 		if ns.namespace != nil {
 			if selector.matches(ns.namespace.ObjectMeta.Labels) {
-				if err := selector.addEntry(string(ns.allPods.ipsetName), namespaceComment(ns)); err != nil {
+				if err := selector.addEntry(ns.namespace.ObjectMeta.UID, string(ns.allPods.ipsetName), namespaceComment(ns)); err != nil {
 					return err
 				}
 			}