copr-hv: lookup for buildsys keys in backend role

roles/copr/hypervisor/tasks/main.yml

@@ -142,8 +142,8 @@
 - name: Assure that copr user on copr-backend can ssh as copr@...
   authorized_key:
     user: copr
-    key: "{{ item }}"
-  with_file:
+    key: "{{ lookup('file', roles_path ~ '/copr/backend/files/provision/files/' ~ item) }}"
+  loop:
     - buildsys.production.pub
     - buildsys.staging.pub