Using a master server, connecting to it and registering a server can cause a crash on a standalone application quit.

To reproduce:
1. Open attached project. It contains a script that registers and hosts a server. It also disconnects and unregisters the host on application quit
2. Open scene Network_scene. Select "Script" in scene and change the master URL to localhost
3. Build windows standalone. (I'm using x86_64)
4. Download the master server and facilitator from http://unity3d.com/master-server
5. Build both of them and run each executable with a parameter (-p 3658 for master server and -p 3659 for facilitator)
6. Run the built unity executable
7. Press "Connect host". It should now connect to your locally hosted master server
8. Press "TestCec" to join the game
9. Try to close the application - the standalone executable crashes

Stack trace does not provide any useful information. If the executable is built as a development build it does not crash.

Explanation: It's crashing on exit because the server instance is connecting to itself, as a client. This is not supported and will result in unpredictable behaviour