taskotron/resultsdb-backend: fix the location of the key in the private repo

The certificates are in pki/issued while the keys are in pki/private.
The location to the CA cert is correct though.

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>

roles/taskotron/resultsdb-backend/tasks/main.yml

@@ -75,7 +75,7 @@
       owner: root
       group: apache
       mode: 0644
-    - src: "{{private}}/files/rabbitmq/{{env}}/pki/issued/resultsdb{{ env_suffix }}.key"
+    - src: "{{private}}/files/rabbitmq/{{env}}/pki/private/resultsdb{{ env_suffix }}.key"
       dest: resultsdb.key
       owner: root
       group: apache