Add support for fedora stein

At stein this tripleo-repos role was wrongly moving to
fedora-stable.repo to delorean-master-testing.repo, this parameterize
this mv with {{ ci_branch }}.

Change-Id: I60b677d6e46c8ef7fa76f1aabe79163b99aa6640
Story: https://tree.taiga.io/project/tripleo-ci-board/us/915

roles/tripleo-repos/tasks/main.yml

@@ -71,5 +71,5 @@
   shell: |
     set -ex
     # Rename fedora-stable.repo as kola.conf.j2 template expects delorean*
-    mv /etc/yum.repos.d/fedora-stable.repo /etc/yum.repos.d/delorean-master-testing.repo
+    mv /etc/yum.repos.d/fedora-stable.repo /etc/yum.repos.d/delorean-{{ ci_branch | default('master') }}-testing.repo
   when: ansible_distribution|lower  == "fedora"