copr: be: make sure we use mock-core-configs contents

... and that we only apply our changes on top of that.

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

@@ -69,6 +69,11 @@
 - name: run /bin/copr-update-builder from copr-builder package
   shell: /usr/bin/copr-update-builder
 
+# temporarily, till https://pagure.io/copr/copr/pull-request/1273 lands
+# production
+- name: restore config files from mock-core-configs
+  shell: find /etc/mock -name '*.rpmnew' | while read file; do mv -f "$file" "${file%%.rpmnew}"; done
+
 - name: put updated mock configs into /etc/mock
   copy: src=files/mock/ dest=/etc/mock
   # conditional, per https://pagure.io/copr/copr/issue/1189 - as we don't want