Change the NOTICE year for Twitter Copyright to 2016

Author: Sijie Guo <sijie@apache.org>

Reviewers: Jia Zhai <zhaijia03@gmail.com>

Closes #127 from sijie/change_notice
diff --git a/NOTICE b/NOTICE
index c9dfcda..dda6c45 100644
--- a/NOTICE
+++ b/NOTICE
@@ -9,4 +9,4 @@
 ===============================================================================
 
 Portions of this software were developed by Twitter.
-Copyright Twitter, 2017
+Copyright Twitter, 2016