Add CHANGES.txt entry and instructions in upgrading.txt for issue2550765/a099ff2ceff3.

Author: ezio-melotti

CHANGES.txt

@@ -22,6 +22,9 @@ Fixed:
 
 - issue2550765: Don't show links in calendar that will fail.
   Found and fixed by C�dric Krier. (Bernhard)
+- issue2550765: use <meta name="robots" content="noindex, nofollow"> in the
+  _generic.calendar.html to prevent robots to follow all the links in the
+  calendar. (Ezio Melotti)
 - "BaseException.with_traceback" is not available on Python 2, so use
   "raise E, V, T" instead of "raise E(V).with_traceback(T)".  This change was
   originally introduced in 74476eaac38a. (Ezio Melotti)
@@ -33,7 +36,7 @@ Fixed:
   (Thomas Arendsen Hein)
 - issue2550762 Minor Documentation fix in doc/developers.txt, thanks
   to W. Trevor King. (Bernhard Reiter)
-- issue2550766: Minor formatting issues in the docs for date properties, 
+- issue2550766: Minor formatting issues in the docs for date properties,
   thanks John Kristensen. (Bernhard Reiter)
 - issue2550738: Fixes for various documentation typoes,
   thanks Nathan Russell. (John Kristensen)

doc/upgrading.txt

@@ -13,6 +13,17 @@ steps.
 
 .. contents::
 
+Migrating from 1.4.20 to 1.4.21
+===============================
+
+The ``_generic.calendar.html`` page of the instance has been updated to include
+``<meta name="robots" content="noindex, nofollow" />``.  This prevents
+robots to follow all the links in the calendar.  If you haven't modified the
+page on your local instance, you can simply replace it with the one in
+``share/roundup/templates/classic/html/_generic.calendar.html``; if you did,
+you can add the tag manually.  See issue2550765 and changeset a099ff2ceff3.
+
+
 Migrating from 1.4.19 to 1.4.20
 ===============================