ceph-volume: do not raise RuntimeError in util.lsblk
Otherwise it makes `simple scan` calls fail.
```
File "/usr/lib/python3.6/site-packages/ceph_volume/util/disk.py", line 246, in lsblk
raise RuntimeError(f"{device} not found is lsblk report")
RuntimeError: /var/lib/ceph/osd/ceph-0/ not found is lsblk report
```
Fixes: https://tracker.ceph.com/issues/58655
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>
(cherry picked from commit
4f19a0f4e1726466968d610da3b0f753981e44a7)
(cherry picked from commit
259a3d554f53c549b135570f2054c3b5c517f993)