Correct the comment, regarding "upstream".

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1889787 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/tools/server-side/svnpubsub/daemonize.py b/tools/server-side/svnpubsub/daemonize.py
index ec08f92..fd91a3c 100644
--- a/tools/server-side/svnpubsub/daemonize.py
+++ b/tools/server-side/svnpubsub/daemonize.py
@@ -16,8 +16,16 @@
 #
 # ---------------------------------------------------------------------------
 #
-# This software lives at:
-#    http://gstein.googlecode.com/svn/trunk/python/daemonize.py
+# This code is no longer maintained "upstream", so consider this module
+# a "friendly fork" and is canonical for Apache Subversion's purposes.
+#
+# Use of systemd's single-process mechanism and re-launching of a daemon
+# can greatly simplify daemon coding/management. A possibly-svn-relevant
+# example can be found at:
+#   https://github.com/apache/infrastructure-svnauthz
+#
+# Historical locations for this module were found on svn.webdav.org,
+# gstein.googlecode.com, and (most recently) gstein.svn.beanstalkapp.com.
 #
 
 import os