veyron,veyron2: rename runtime.Shutdown to runtime.Cleanup.

Context:
https://docs.google.com/a/google.com/document/d/1Sfq1ZEEPtxMFR2Wj6SFNMlNNXZ9xnuz-Cep73RXmBwI/edit

Change-Id: I20b89e7acf70f97c3216bc155e7afcce0cc5db0a
diff --git a/services/mgmt/node/noded/main.go b/services/mgmt/node/noded/main.go
index af7c5d2..b993371 100644
--- a/services/mgmt/node/noded/main.go
+++ b/services/mgmt/node/noded/main.go
@@ -28,7 +28,7 @@
 		vlog.Fatalf("Specify the node manager origin as environment variable %s=<name>", impl.OriginEnv)
 	}
 	runtime := rt.Init()
-	defer runtime.Shutdown()
+	defer runtime.Cleanup()
 	server, err := runtime.NewServer()
 	if err != nil {
 		vlog.Fatalf("NewServer() failed: %v", err)