cephadm-adopt: remove legacy directory after adoption

cephadm-adopt: remove legacy directory after adoption

When this directory is left after the osd adoption, it leads to the following error:

```
[WRN] CEPHADM_REFRESH_FAILED: failed to probe daemons or devices
    host axdesec2ocs1n002.ecommerce.inditex.grp `cephadm ceph-volume` failed: cephadm exited with an error code: 1, stderr:Inferring config /var/lib/ceph/41555360-e96b-4b16-a37c-873e0c940091/mon.axdesec2ocs1n002/config
ERROR: [Errno 2] No such file or directory: '/var/lib/ceph/41555360-e96b-4b16-a37c-873e0c940091/mon.axdesec2ocs1n002/config'.
```

this is because of an unexpected behavior regarding 'config inferring' when a legacy directory is present in /var/lib/ceph.

Note: this doesn't fix the root cause, this is a workaround.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2075510
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>