无法使用滑行获取子模块

https://github.com/Masterminds/glide

I try to use glide with Azure go sdk.

https://github.com/Azure/azure-sdk-for-go

In this repository, it uses submodule.

I create a simple glide.yaml like this.

package: cf-engine
import:
- package: github.com/Azure/azure-sdk-for-go

then

glide install

However, the submodule directory(storage) still empty. I tried

glide update --all-dependencies

Also it is still the empty.

I tried go get. Then the submodule directory was filled.

 go get github.com/Azure/azure-sdk-for-go

How can I fetch the submodule directory using glide?