Fluentd: Filter out fluentd's logs

This filters out fluentd's logs for collection, as this can result
in infinite loops as fluentd will try to process the events in its
own logs repeatedly

Change-Id: I85cce909b6917901b964cb5cc479403143c4d211

fluent-logging/values.yaml

@@ -118,6 +118,10 @@ conf:
         DB.Sync: Normal
         Buffer_Chunk_Size: 1M
         Buffer_Max_Size: 1M
+    - drop_fluentd_logs:
+        header: output
+        Name: "null"
+        Match: "**.fluentd**"
     - kube_filter:
         header: filter
         Name: kubernetes
@@ -148,6 +152,10 @@ conf:
         type: forward
         port: "#{ENV['FLUENTD_PORT']}"
         bind: 0.0.0.0
+    - filter_fluentd_logs:
+        header: match
+        expression: "fluent.**"
+        type: "null"
     - elasticsearch:
         header: match
         type: elasticsearch