lib/time: update to IANA release 2016d (Apr 2016).

Change-Id: I46d9ea31cf5836d054a9ce22af4dd1742a418a07
Reviewed-on: https://go-review.googlesource.com/22588
Run-TryBot: David Symonds <dsymonds@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

lib/time/update.bash

@@ -8,8 +8,8 @@
 # Consult http://www.iana.org/time-zones for the latest versions.
 
 # Versions to use.
-CODE=2016a
-DATA=2016a
+CODE=2016d
+DATA=2016d
 
 set -e
 rm -rf work