Surface Error Message from the UI

[boumenot]

Sometime when deployment fails the response via the API is simply "failed" without an explanation as to why. The UI provides a more appropriate error message that allows the user to debug the problem, and make progress. packer-azure should fetch these messages, and display them to the user.

The operation "Write Deployments" tends (always?) to have the failed event.
-> Microsoft.Resources/deployments/write

[boumenot]

There have been some recent improvements in the Go SDK and go-autorest that should improve this considerably. Please investigate.