Fix incorrect use of splice

loaders/src/glTF/2.0/babylon.glTFLoader.ts

@@ -1162,7 +1162,7 @@ module BABYLON.GLTF2 {
 
         public _whenAction(action: () => void, onComplete: () => void): void {
             const tracker = new GLTFLoaderTracker(() => {
-                this._loaderTrackers.splice(this._loaderTrackers.indexOf(tracker));
+                this._loaderTrackers.splice(this._loaderTrackers.indexOf(tracker), 1);
                 onComplete();
             });
 

src/Bones/babylon.bone.ts

@@ -74,7 +74,7 @@ module BABYLON {
             if (this._parent) {
                 var index = this._parent.children.indexOf(this);
                 if (index !== -1) {
-                    this._parent.children.splice(index);
+                    this._parent.children.splice(index, 1);
                 }
             }