MAPREDUCE-6268. Fix typo in Task Attempt API's URL. Contributed by Ryu Kobayashi.

(cherry picked from commit 742f9d90c00f823ad7fea7e79702fcf238fa5721)

Conflicts:
	hadoop-mapreduce-project/CHANGES.txt
	hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/site/markdown/HistoryServerRest.md

hadoop-mapreduce-project/CHANGES.txt

@@ -151,6 +151,9 @@ Release 2.7.0 - UNRELEASED
     MAPREDUCE-2815. JavaDoc does not generate correctly for
     MultithreadedMapRunner. (Chris Palmer via aajisaka)
 
+    MAPREDUCE-6268. Fix typo in Task Attempt API's URL. (Ryu Kobayashi
+    via ozawa)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/site/apt/HistoryServerRest.apt.vm

@@ -2137,7 +2137,7 @@ MapReduce History Server REST API's.
   Use the following URI to obtain an Task Attempt Object, from a task identified by the {attemptid} value. 
 
 ------
-  * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}/attempt/{attemptid}
+  * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}/attempts/{attemptid}
 ------
 
 *** HTTP Operations Supported