cube: Fix fixup_bundle not set to proper cube
cube: Fix fixup_bundle not set to proper cube

Changed fixup_bundle pointing at cube.app and
cubepp.app to point to vkcube.app and vkcubepp.app

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools