func osDiskStorageBlobURL(account *storage.AccountProperties, vmName string) string {
	containerURL := osDiskStorageContainerURL(account, vmName) // has trailing slash
	blobName := fmt.Sprintf(fmtOSDiskBlobName, vmName)
	return containerURL + blobName
}
func osDiskStorageBlobURL(account *storage.AccountProperties, vmName string) string {
	containerURL := osDiskStorageContainerURL(account, vmName) // has trailing slash
	blobName := fmt.Sprintf(fmtOSDiskBlobName, vmName)
	return containerURL + blobName
}
// osDiskStorageBlobURL gives the full url of the VHD blob where the OS disk for
// the given VM should be stored.