try how it behave in dev instance with new mock

roles/copr/backend/files/provision/provision_builder_tasks.yml

@@ -26,6 +26,7 @@
     - rpm
     - glib2
     - ca-certificates
+    - https://kojipkgs.fedoraproject.org//packages/mock/1.2.9/1.fc21/noarch/mock-1.2.9-1.fc21.noarch.rpm
 
 - name: put updated mock configs into /etc/mock
   copy: src=files/mock/{{ item }} dest=/etc/mock