bridge: make the cache-sync channel buffered to avoid a goroutine leak

On timeout the manager goroutine still finishes WaitForCacheSync and
closes the synced channel, but nobody reads it: on an unbuffered channel
that close blocks forever. A buffer of one lets the goroutine finish.

pkg/bridge/lookup.go

@@ -58,7 +58,7 @@ func NewManagerForClientWithTimeout(client kubernetes.Interface, timeout time.Du
 	m := runtimeclass.NewManager(client)
 	stop := make(chan struct{})
 	m.Start(stop)
-	synced := make(chan struct{})
+	synced := make(chan struct{}, 1)
 	go func() {
 		m.WaitForCacheSync(stop)
 		close(synced)