TransportBroker NPE

[JulianKast]

Description

TransportBroker.shutDownRouterServiceMessenger hitting NPE, likely due to routerServiceMessenger being set to null before we close routerServiceMessageEmitter. This NPE was hit by accident, testing custom RS logic with an incorrect app. The code referenced with this NPE has not been released yet and is only on the RC.

E  FATAL EXCEPTION: RouterServiceMessageEmitter
                                      Process: com.sdl.hellosdlandroid, PID: 17777
                                      java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.IBinder android.os.Messenger.getBinder()' on a null object reference
                                      at com.smartdevicelink.transport.TransportBroker.sendMessageToRouterService(TransportBroker.java:153)
                                      at com.smartdevicelink.transport.TransportBroker$1$1.onMessageToSend(TransportBroker.java:116)
                                      at com.smartdevicelink.transport.RouterServiceMessageEmitter.run(RouterServiceMessageEmitter.java:32)

[joeygrover]

Closed with #1882