update GC controller to wait until controllers have been initialized once

pkg/controller/garbagecollector/graph_builder.go

@@ -78,6 +78,10 @@ type GraphBuilder struct {
 	// dependencyGraphBuilder
 	monitors    monitors
 	monitorLock sync.Mutex
+	// informersStarted is closed after after all of the controllers have been initialized and are running.
+	// After that it is safe to start them here, before that it is not.
+	informersStarted <-chan struct{}
+
 	// stopCh drives shutdown. If it is nil, it indicates that Run() has not been
 	// called yet. If it is non-nil, then when closed it indicates everything
 	// should shut down.
@@ -279,6 +283,10 @@ func (gb *GraphBuilder) startMonitors() {
 		return
 	}
 
+	// we're waiting until after the informer start that happens once all the controllers are initialized.  This ensures
+	// that they don't get unexpected events on their work queues.
+	<-gb.informersStarted
+
 	monitors := gb.monitors
 	started := 0
 	for _, monitor := range monitors {