Fix key-checking in events extracted from RabbitMQ

Change-Id: I4d9eafc389af8e77ddd75ac5034ad2c21ec7e028
Related-PROD: PROD-35949
diff --git a/fluentd/label/notifications/input_rabbitmq.yml b/fluentd/label/notifications/input_rabbitmq.yml
index 3d7edef..06fca7c 100644
--- a/fluentd/label/notifications/input_rabbitmq.yml
+++ b/fluentd/label/notifications/input_rabbitmq.yml
@@ -85,7 +85,7 @@
                 enable_ruby: true
                 record:
                   - name: notification_type
-                    value: '${fluentd:dollar}{ record["payload"]["eventType"] && record["payload"]["eventTime"] ? "audit" : "notification" }'
+                    value: '${fluentd:dollar}{ record["payload"].key?("eventType") && record["payload"].key?("eventTime") ? "audit" : "notification" }'
             match:
               rewrite_message_tag:
                 tag: raw_notifications