A small comment still pointed to NIH tzdata server

diff --git a/dateutil/tz.py b/dateutil/tz.py
index e1976db..e849fc2 100644
--- a/dateutil/tz.py
+++ b/dateutil/tz.py

@@ -208,7 +208,7 @@
 class tzfile(datetime.tzinfo):
 
     # http://www.twinsun.com/tz/tz-link.htm
-    # ftp://elsie.nci.nih.gov/pub/tz*.tar.gz
+    # ftp://ftp.iana.org/tz/tz*.tar.gz
     
     def __init__(self, fileobj):
         if isinstance(fileobj, string_types):