osd: do not use dm when osd_auto_discovery

The current code will also return lvm devices such as /dev/dm-2, this
kind of device type is not supported by ceph-disk at the moment. Now we
just ignore them.

Signed-off-by: Sébastien Han <seb@redhat.com>

roles/ceph-osd/tasks/main.yml

@@ -28,6 +28,7 @@
     - item.value.removable == "0"
     - item.value.partitions|count == 0
     - item.value.holders|count == 0
+    - "'dm-' not in item.key"
 
 - name: include check_devices.yml
   include: check_devices.yml