Set default interval to 40s when Jewel Ceph in use

Change-Id: I904787671c2f380965ef939e76164df69341279f
Closes-Bug: PROD-26842
diff --git a/ceph/meta/telegraf.yml b/ceph/meta/telegraf.yml
index cbbe981..1c0a42e 100644
--- a/ceph/meta/telegraf.yml
+++ b/ceph/meta/telegraf.yml
@@ -25,9 +25,7 @@
         {%- if monitoring.cluster_stats.osd_prefix is defined %}
       osd_prefix: {{ monitoring.cluster_stats.osd_prefix }}
         {%- endif %}
-        {%- if monitoring.interval is defined %}
-      interval: {{ monitoring.interval }}
-        {%- endif %}
+      interval: {{ monitoring.interval | default('40s') }}
       {%- else  %}
       ceph_user: client.admin
       gather_admin_socket_stats: false