Fix nogui build, and fix a minor issue with the GFX config dialogs when backends are changed.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@7042 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Plugins/Plugin_VideoDX9/Src/main.cpp

@@ -145,6 +145,7 @@ void VideoBackend::ShowConfig(void* parent)
 	diag->ShowModal();
 	diag->Destroy();
 
+	g_Config.backend_info.Adapters.clear();
 	DX9::D3D::Shutdown();
 #endif
 }