Fix Livepatch status reporting bug

[srunde3]

Fix issue in which pro status inaccurately displays Livepatch status as "disabled" even if it is active. Bug is due to the landscape user not being able to run snaps properly since it has a $HOME directory outside of /home (it's in /var/lib/).

See https://bugs.launchpad.net/landscape-client/+bug/2037670

Manual Testing:

• Spin up a VM with a Livepatch-supported kernel
• Modify UbuntuProInfo.run_interval to be something quick like 10
• Modify landscape-client.conf to point to a Landscape Server instance. Additionally include exchange_interval = 10` to exchange messages with server more quickly
• sudo scripts/landscape-monitor --config landscape-client.conf
• Toggle livepatch and ensure updates are reflected in Server sudo pro <enable/disable> livepatch

[silverdrake11]

According to the this comment in get_data()

New messages will only be sent
    when the result of get_data() has changed since the last time it
    was called.

However I believe it only works for monitor DataWatcher. If it works this would cut down traffic from once every 15 minutes to once a day or less. I think it's worth caching it, but I don't think it's currently working. See _persist in landscape/client/monitor/plugin.py for how this works. I'm not sure if the best way to do it is to make a new class, make existing one work, or just define a function in ubuntupro

[silverdrake11]

Why was net-tools added as a dependency?

[Perfect5th]

Why was net-tools added as a dependency?

It's required for some of the unit tests to pass. It's a build dep in debian/control. I'm not sure why it's needed in DEB_REQUIRED though.

[srunde3]

That's my mistake then -- it should go in debian/control instead of DEB_REQUIRED. I added it because it was required for tests to pass

[srunde3]

Moved net-tools dependency into Makefile instead of setup_lib::DEB_REQUIRED

[Perfect5th]

LGTM, may want to wait for @silverdrake11 to re-review, though.

[silverdrake11]

LGTM except for the name data that you are persisting to. It would be better to have it be more specific name since this is only used for ubuntu pro manager and not other kinds of data

[srunde3]

Discussed offline with @silverdrake11 -- fine to use data since persist should be unique to UbuntuProInfo based on file path.