Buggy behaviour when using --version flag

[Juan M. Tirado]

The `--version` flag forces a buggy behaviour in Juju. See these examples:

juju bootstrap --version
ERROR unknown cloud "version", please try "juju update-public-clouds"

juju status --version
<hanged>

juju model --version
<hanged>

[Juan M. Tirado (tiradojm)]

After running `juju update-public-clouds` `juju bootstrap --version` continues showing the same error.

[Robert Gildein (rgildein)]

I hit similar issue with our plugin called `juju-spell`.

This issue occurs as follows.
```bash
$ juju spell --version
# debug print ['/home/rgildein/code/canonical/multijuju/.venv/bin/juju-spell', 'version']
Usage: juju-spell [options] command [args]...
Try 'juju-spell -h' for help.

Error: no such command 'version'

$ juju-spell --version
['/home/rgildein/code/canonical/multijuju/.venv/bin/juju-spell', '--version']
JujuSpell: 0.0.1
```

It look like that juju will remove `--` and pass only `version`.

I'm using juju "2.9.38-ubuntu-amd64" version.