purge-docker: fix ceph-osd-zap name container

purge-docker: fix ceph-osd-zap name container

the `zap ceph osd disks` task should iter on `resolved_parent_device`
instead of `combined_devices_list` which contain only the base device
name (vs. full path name in `combined_devices_list`).

this fixes the issue where docker complain about container name because
of illegal characters such as `/` :
```
"/usr/bin/docker-current: Error response from daemon: Invalid container
name (ceph-osd-zap-magna074-/dev/sdb1), only [a-zA-Z0-9][a-zA-Z0-9_.-]
are allowed.","See '/usr/bin/docker-current run --help'."
""
```

having the the basename of the device path is enough for the container
name.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1540137
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>