Code review comment for ~dojordan/cloud-init:azure-preprovisioning

As it is right now, 'bounce_network_with_azure_hostname' is a no-op
on Ubuntu 18.04 (bionic) or any system without 'ifup'.
So while you want this fixed in 16.04, the general Ubuntu development
path insists that we make things work on the development release first
and the SRU them back to 16.04.

In summary: I can't let this in as broken on bionic. We'll need to find
a way to make that work on 18.04.

Your commit message says:
 | This change will enable azure vms to report provisioning has completed
 | twice, first to tell the fabric it has completed then a second time to
 | enable customer settings.

Is that true, will it *always* report reprovisioning has completed twice?

there are some small inlinel things also.

those are the big things though. thanks for your work.