aptly mirror parametrization

PROD-15379

Change-Id: Icff58138405245e968d63539ec7b0df2a313b6fd
diff --git a/aptly/server/mirror/ubuntu/trusty/grafana.yml b/aptly/server/mirror/ubuntu/trusty/grafana.yml
index 68ff86a..16c4124 100644
--- a/aptly/server/mirror/ubuntu/trusty/grafana.yml
+++ b/aptly/server/mirror/ubuntu/trusty/grafana.yml
@@ -1,14 +1,19 @@
 parameters:
+  _param:
+    mirror_grafana-trusty_source: https://packagecloud.io/grafana/stable/debian/
+    mirror_grafana-trusty_distribution: wheezy
+    mirror_grafana-trusty_components: main
+    mirror_grafana-trusty_gpgkeys:
+      - D59097AB
   aptly:
     server:
       mirror:
         grafana-trusty:
-          source: https://packagecloud.io/grafana/stable/debian/
-          distribution: wheezy
-          components: main
+          source: ${_param:mirror_grafana-trusty_source}
+          distribution: ${_param:mirror_grafana-trusty_distribution}
+          components: ${_param:mirror_grafana-trusty_components}
           architectures: amd64
-          gpgkeys:
-            - D59097AB
+          gpgkeys: ${_param:mirror_grafana-trusty_gpgkeys}
           publisher:
             component: grafana
             distributions: