Code review comment for lp:~frankban/juju-quickstart/handle-machine-errors

Reviewers: mp+202105_code.launchpad.net,

Message:
Please take a look.

Description:
Improve machine errors handling.

Quickstart no longer hangs when the GUI
machine goes in an "error" state and, as
a consequence, the unit is forever in
a "pending" state.

Also fixed the message printed at the
end of the process suggesting how to
destroy the environment
(sudo is used where required).

Tests: `make check`.

QA: I already asked Rick to reproduce the trusty/LXC
errors he encountered QAing my previous branch.
The GUI no longer hangs.
I'd also appreciate any other suggestion and additional
QA, given that this branch is a good candidate for 1.0.

https://code.launchpad.net/~frankban/juju-quickstart/handle-machine-errors/+merge/202105

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/51350044/

Affected files (+616, -180 lines):
   A [revision details]
   M quickstart/app.py
   M quickstart/manage.py
   M quickstart/tests/test_app.py
   M quickstart/tests/test_utils.py
   A quickstart/tests/test_watchers.py
   M quickstart/utils.py
   A quickstart/watchers.py