sdl: clear SDL.NetworkIP config on CloseGame() to prevent reconnection on next loadGame() call

src/drivers/sdl/sdl.cpp

@@ -239,6 +239,9 @@ CloseGame()
 	if(filename.size()) {
 		FCEUI_EndWaveRecord();
 	}
+  // LoadGame() checks for an IP and if it finds one begins a network session
+  // clear the NetworkIP field so this doesn't happen unintentionally
+  g_config->setOption("SDL.NetworkIP", "");
 
 	InputUserActiveFix();
 	return(1);