[branch-0.9] Update CHANGES.txt

Author: Xiangrui Meng <meng@databricks.com>

Closes #1459 from mengxr/v0.9.2-rc and squashes the following commits:

6fa5a65 [Xiangrui Meng] update CHANGES.txt
diff --git a/CHANGES.txt b/CHANGES.txt
index 9720669..6306963 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
Binary files differ