Use new tag_rewrite format

Previous syntax was deprecated

Change-Id: I16fb5284aa4d5c4e05daeeadad661ca7067f4632
diff --git a/fluentd/files/match/rewrite_tag_filter.conf b/fluentd/files/match/rewrite_tag_filter.conf
index b62f24f..3e8a164 100644
--- a/fluentd/files/match/rewrite_tag_filter.conf
+++ b/fluentd/files/match/rewrite_tag_filter.conf
@@ -1,6 +1,10 @@
 <match {{ values.tag }}>
   @type rewrite_tag_filter
   {%- for rule in values.rule %}
-  rewriterule{{ loop.index }} {{ rule.name }} {{ rule.regexp }} {{ rule.result }}
+  <rule>
+    key {{ rule.name }}
+    pattern {{ rule.regexp }}
+    tag {{ rule.result }}
+  </rule>
   {%- endfor %}
 </match>