coreos-cincinnati: use templated build ref

roles/openshift-apps/coreos-cincinnati/templates/buildconfig-stub.yml

@@ -1,5 +1,4 @@
 ---
-# TODO(lucab): template refs from ansible var
 apiVersion: v1
 kind: BuildConfig
 metadata:
@@ -21,10 +20,10 @@ spec:
     type: "Git"
     git:
       uri: "https://github.com/lucab/exp-dumnati.git"
-      ref: "124d9475717eae13cf2e76a8a455f0ee542a75cb"
+      ref: "{{dumnati_build_git_sha}}"
   triggers:
     - type: "ConfigChange"
   output:
     to:
       kind: "ImageStreamTag"
-      name: "fedora-coreos-cincinnati:dumnati-124d9475717eae13cf2e76a8a455f0ee542a75cb"
+      name: "fedora-coreos-cincinnati:dumnati-{{dumnati_build_git_sha}}"

roles/openshift-apps/coreos-cincinnati/vars/production.yml

@@ -1 +1,2 @@
 ---
+dumnati_build_git_sha: 124d9475717eae13cf2e76a8a455f0ee542a75cb

roles/openshift-apps/coreos-cincinnati/vars/staging.yml

@@ -1 +1,2 @@
 ---
+dumnati_build_git_sha: 124d9475717eae13cf2e76a8a455f0ee542a75cb