LoadingManager wrong itemsTotal

Hey!

There is a problem!

When I load even one gltf file (no textures, etc.) LoadingManager onProgress shows wrong itemsTotal. in fact, if there is only one gltf file, then itemsTotal = 2

http://joxi.ru/Y2L5ODvHMvz38A

What you see is the effect of a workaround in GLTFLoader to ensure LoadingManager.onLoad() is fired correctly.

Oh! thank you very much!