Comment 14 for bug 2012306

$ cat /var/lib/juju/tools/2.9.42-ubuntu-amd64/downloaded-tools.txt
{"version":"2.9.42-ubuntu-amd64","url":"https://172.16.1.99:17070/model/6a346a06-9197-4f52-8ee7-7a62c58ea30b/tools/2.9.42-ubuntu-amd64","sha256":"10617ce334ef9e00efbcfd06f072687bfac1071b54bc910b491c940ec598877f"
,"size":42029399}

In my case it was a landscape-rmq unit.

I was able to get it to work with a
juju_stop_unit landscape-rabbitmq/4
juju_start_unit landscape-rabbitmq/4

(and also a restart of the rmq server)

and then,
/var/lib/juju/agents/unit-landscape-rabbitmq-4/agent.conf:upgradedToVersion: 2.9.42

and logs did not complain about,
```
failed to fetch agent binaries from "": Get "": unsupported protocol scheme ""
```