Don't let fluentd pipe its own logs directly back into itself.

cluster/addons/fluentd-elasticsearch/fluentd-es-image/td-agent.conf

@@ -100,6 +100,11 @@
 # problem yet to be solved as secrets are not usable in static pods which the fluentd
 # pod must be until a per-node controller is available in Kubernetes.
 
+# Do not directly collect fluentd's own logs to avoid infinite loops.
+<match fluent.**>
+  type null
+</match>
+
 <source>
   type tail
   path /var/log/containers/*.log