spinnaker-jenkins-to-vmss deployment to azure failed

When deploying to azure this example [here](https://github.com/Azure/azure-quickstart-templates/tree/master/spinnaker-jenkins-to-vmss) fails on the VMExtensionProvision step with the following error:

`"message": "VM has reported a failure when processing extension 'SpinnakerCustomScript'.
Error message: \"Enable failed: failed to execute command: command terminated with exit status=1\"."
`

Start with the spinnaker-jenkins-to-vmss example linked in the issue and inspect the VMExtensionProvision step and SpinnakerCustomScript extension. Reproduce the Azure deployment to capture the command failure, then identify and fix the cause so the example completes successfully without the VM extension error.

Written by the indexing model from the issue text.