Configure InfluxDB retention policy

https://github.com/Mirantis/mk-lab-salt-model/pull/178
diff --git a/influxdb/server/single.yml b/influxdb/server/single.yml
index 308b7be..ce76490 100644
--- a/influxdb/server/single.yml
+++ b/influxdb/server/single.yml
@@ -30,6 +30,11 @@
         lma:
           enabled: true
           name: lma
+          retention_policy:
+          - name: lma
+            is_default: true
+            duration: 30d
+            replication: 1
       user:
         lma:
           enabled: true