Fix pos_file location

Change-Id: Ifa2787d76cf18e29f54583046349c071c5e9a25e
diff --git a/linux/meta/fluentd.yml b/linux/meta/fluentd.yml
index 6ee5e4f..c2e5b77 100644
--- a/linux/meta/fluentd.yml
+++ b/linux/meta/fluentd.yml
@@ -6,7 +6,7 @@
           type: systemd
           tag: systemd.source
           path: /run/log/journal
-          pos_file: /tmp/fluentd-systemd.pos
+          pos_file: /var/log/td-agent/tmp/systemd.source.pos
           entry:
             field_map:
               MESSAGE: 'Payload'