[tz] tz-announce list is incorrectly configured

[Alan Barrett]

Once again, a message has appeared on the tz-announce list 
without also appearing on the tz list.  In this case, it was an 
announcement that the 2013d releases of txcode and tzdata are 
available.

Please could the tz-announce list be configured such that it is 
impossible for a message to go to tz-announce at iana.org without 
also going to tz at iana.org.  tz-announce was always intended to 
carry a subset of the messages sent to the tz list, not to carry 
some disjoint or partially-overlapping set of messages.

It's unreasonable to expect readers to subscribe to both lists in 
order to see all messages, and it's also unreasonable to expect 
people who send announcements to CC both lists to ensure that the 
tz list receives all messages.  This really should be fixed at the 
mailing list server side.

--apb (Alan Barrett)