Hotplug traceback on openstack bionic

This bug was originally filed in Launchpad as [LP: #1942247](https://bugs.launchpad.net/cloud-init/+bug/1942247)

Launchpad details

affected_projects = []

assignee = None

assignee_name = None

date_closed = None

date_created = 2021-08-31T19:17:54.574613+00:00

date_fix_committed = None

date_fix_released = None

id = 1942247

importance = medium

is_complete = False

lp_url = https://bugs.launchpad.net/cloud-init/+bug/1942247

milestone = None

owner = falcojr

owner_name = James Falcon

private = False

status = triaged

submitter = falcojr

submitter_name = James Falcon

tags = []

duplicates = []

_Launchpad user **James Falcon(falcojr)** wrote on 2021-08-31T19:17:54.574613+00:00_

On Openstack, when responding to a hotplug event, we traceback attempting to detect the updated metdata:
https://github.com/canonical/cloud-init/blob/main/cloudinit/cmd/devel/hotplug_hook.py#L143

This is due to the network data being set to None here:
https://github.com/canonical/cloud-init/blob/main/cloudinit/sources/DataSourceOpenStack.py#L117

We should gracefully handle getting no network metdata.

This doesn't prevent the hotplug action from completing successfully. This is in the code to detect that metadata has been updated successfully post hotplug.