juju[2.9.3] bootstrap controller failed on microstack

[Robert Gildein]

I tried to use a microstack as a cloud for Juju, but bootstrapping [1] the controller failed with timeout error:
`ERROR juju.cmd.juju.commands bootstrap.go:881 contacting controller (cancelled): dial tcp 192.168.222.222:17070: i/o timeout`

I could not find any error message in the logs. (cloud-init.log, cloud-init-output.log, qemu/*.log [3])

Environment VM[12cpus, 24GB ram, 100GB disk:
```
ubuntu@microstack:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.2 LTS
Release: 20.04
Codename: focal

ubuntu@microstack:~$ sudo snap list juju
Name Version Rev Tracking Publisher Notes
juju 2.9.3 16337 2.9/stable canonical✓ classic
```

After switching to juju 2.8.10 it work fine.

It could be reproduced with [2].
---
[1]: https://pastebin.ubuntu.com/p/RTnr4yYxvk/
[2]: https://pastebin.ubuntu.com/p/vFYG6Y22T8/
[3]: https://pastebin.ubuntu.com/p/4xgNs7ZYn9/