Updated CHANGES.txt for YARN-4328.

hadoop-yarn-project/CHANGES.txt

@@ -56,6 +56,8 @@ Release 2.7.4 - UNRELEASED
     YARN-3432.  Cluster metrics have wrong Total Memory when there is reserved
     memory on CS. (Brahma Reddy Battula via curino)
 
+    YARN-4328. Fix findbugs warnings in resourcemanager (Akira Ajisaka via Varun Saxena)
+
     YARN-5001. Aggregated Logs root directory is created with wrong group if
     nonexistent (Haibo Chen via jlowe)