osd: fix `set_fact build dedicated_devices`

Use an intermediate variable to build the final `dedicated_devices` list
to avoid duplicate entry in that array. (We need a 1:1 relation between
`dedicated_devices` and `devices` since we are using a `with_together`
later.

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

roles/ceph-osd/tasks/check_devices.yml

@@ -20,14 +20,14 @@
 
 - name: set_fact build dedicated_devices from resolved symlinks
   set_fact:
-    dedicated_devices: "{{ dedicated_devices | default([]) + [ item.stdout ] }}"
+    dedicated_devices_tmp: "{{ dedicated_devices_tmp | default([]) + [ item.stdout ] }}"
   with_items: "{{ dedicated_devices_prepare_canonicalize.results }}"
   when:
     - osd_scenario == 'non-collocated'
 
 - name: set_fact build final dedicated_devices list
   set_fact:
-    dedicated_devices: "{{ dedicated_devices | reject('search','/dev/disk') | list }}"
+    dedicated_devices: "{{ dedicated_devices_tmp | reject('search','/dev/disk') | list }}"
   when:
     - osd_scenario == 'non-collocated'