HDFS-6694. Addendum. Update CHANGES.txt for cherry-picking to 2.8.

(cherry picked from commit 84d01ad7f43bc498bc2e9d3afe68aed7f4a4d462)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1522,6 +1522,10 @@ Release 2.8.0 - UNRELEASED
     HDFS-8335. FSNamesystem should construct FSPermissionChecker only if
     permission is enabled. (Gabor Liptak via wheat9)
 
+    HDFS-6694. TestPipelinesFailover.testPipelineRecoveryStress tests fail
+    intermittently with various symptoms - debugging patch. (Yongjun Zhang via
+    Arpit Agarwal)
+
 Release 2.7.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES