Fix additional panic

Ensure we take the incomingBlock Lock
in blockQueue to ensure there
is not any possiblity of sending on a
closed incoming channel.

Signed-off-by: Andrew Stoycos <astoycos@redhat.com>

staging/src/k8s.io/apimachinery/pkg/watch/mux.go

@@ -46,7 +46,7 @@ type Broadcaster struct {
 	distributing sync.WaitGroup
 
 	// incomingBlock allows us to ensure we don't race and end up sending events
-	// to a closed channel following a brodcaster shutdown.
+	// to a closed channel following a broadcaster shutdown.
 	incomingBlock sync.Mutex
 	incoming      chan Event
 	stopped       chan struct{}
@@ -115,6 +115,8 @@ func (obj functionFakeRuntimeObject) DeepCopyObject() runtime.Object {
 // won't ever see that event, and will always see any event after they are
 // added.
 func (m *Broadcaster) blockQueue(f func()) {
+	m.incomingBlock.Lock()
+	defer m.incomingBlock.Unlock()
 	select {
 	case <-m.stopped:
 		return
@@ -252,8 +254,6 @@ func (m *Broadcaster) ActionOrDrop(action EventType, obj runtime.Object) (bool,
 // have received the data yet as it can remain sitting in the buffered
 // channel. It will block until the broadcaster stop request is actually executed
 func (m *Broadcaster) Shutdown() {
-	m.incomingBlock.Lock()
-	defer m.incomingBlock.Unlock()
 	m.blockQueue(func() {
 		close(m.stopped)
 		close(m.incoming)