Azure Storage Connection Error

> Please provide us with the following information:
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### This issue is for a: (mark with an `x`)
```
- [X] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
> Cannot get the app package from azure storage and you will get "System cannot find the path specified" error since the connection string missing ` EndpointSuffix=core.windows.net`.

### Any log messages given by the failure
>

### Expected/desired behavior
>

### OS and Version?
> Windows 7, 8 or 10. Linux (which distribution). macOS (Yosemite? El Capitan? Sierra?)

### Versions
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### Mention any other details that might be useful

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> Thanks! We'll be in touch soon.

在 batch-dotnet-ffmpeg-tutorial 應用程式中，先找出用於擷取應用程式套件的 Azure Storage 連接字串。重現缺少路徑的錯誤，確認連接字串包含回報的 EndpointSuffix 值，然後確認應用程式套件可以成功下載。

由索引模型根據 Issue 內容生成。