HADOOP-12186. ActiveStandbyElector shouldn't call monitorLockNodeAsync multiple times (Contributed by zhihai xu)

Moved CHANGES.txt entry to 2.7.2

(cherry picked from commit e0febce0e74ec69597376774f771da46834c42b1)

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

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -436,9 +436,6 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12173. NetworkTopology::add calls toString always.
     (Inigo Goiri via cdouglas)
 
-    HADOOP-12186. ActiveStandbyElector shouldn't call monitorLockNodeAsync
-    multiple times (zhihai xu via vinayakumarb)
-
     HADOOP-12185. NetworkTopology is not efficient adding/getting/removing
     nodes. (Inigo Goiri via cdouglas)
 
@@ -457,6 +454,9 @@ Release 2.7.2 - UNRELEASED
 
   BUG FIXES
 
+    HADOOP-12186. ActiveStandbyElector shouldn't call monitorLockNodeAsync
+    multiple times (zhihai xu via vinayakumarb)
+
 Release 2.7.1 - 2015-07-06 
 
   INCOMPATIBLE CHANGES