mounted ephemeral disk - not self-describing blocked message

[Robert Gildein]

If a ephemeral disk is mount, the unit will ends in blocked workload with not
self-describing message.

```bash
Unit Workload Agent Machine Public address Ports Message
ceph-osd/0* blocked idle 0 10.245.163.249 No block devices detected using current configuration
```

There should be a message that the drive is mounted and the user should use the
"ephemeral-unmount=<device>" configuration.

Here are steps [1] needed to fix ceph-osd units.

---
[1]: https://pastebin.ubuntu.com/p/Pf8DHnVcD2/