Sets the release date for 3.1.17

Changelog

@@ -12,6 +12,8 @@ new in Celery 3.1.
 
 3.1.17
 ======
+:release-date: 2014-11-19 03:30 P.M UTC
+:release-by: Ask Solem
 
 .. admonition:: Do not enable the :setting:`CELERYD_FORCE_EXECV` setting!