fix root access node lookup

Author: metacoma

files/logstash/pipeline/kubernetes.conf

@@ -18,7 +18,9 @@ host = event.get("[kubernetes][host]").to_s
 log = event.get("log").to_s
 groovy_code = Base64.strict_encode64("
 
-namespace_node = node.find{it.text == \"#{namespace_node}\"}
+root_node = c.getViewRoot()
+
+namespace_node = root_node.find{it.text == \"#{namespace_node}\"}
 if (namespace_node) {
     namespace_node = namespace_node[0]
   } else {