Fix resync goroutine leak in ListAndWatch

Previously, we had no way to stop resync goroutine when ListAndWatch
returned.  goroutine leaked every time ListAndWatch returned, for
example, with error.  This commit adds another channel to signal that
resync goroutine should exit when ListAndWatch returns.

pkg/client/cache/reflector.go

@@ -259,12 +259,16 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 	r.setLastSyncResourceVersion(resourceVersion)
 
 	resyncerrc := make(chan error, 1)
+	cancelCh := make(chan struct{})
+	defer close(cancelCh)
 	go func() {
 		for {
 			select {
 			case <-resyncCh:
 			case <-stopCh:
 				return
+			case <-cancelCh:
+				return
 			}
 			glog.V(4).Infof("%s: forcing resync", r.name)
 			if err := r.store.Resync(); err != nil {