MAPREDUCE-7282: remove v2 commit algorithm for correctness reasons.

[steveloughran]

• All jobs requsting v2 algorithm are WARNED and then switched to v1.
• the v2 codepaths in file output committer have been removed, even
  though some of the method names "rename or merge" are unchanged.

This patch doesn't fix those tests which will fail; I have
those changed and will submit after a Yetus run, to show what breaks/
is fixed

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Comment
+0 🆗	reexec	0m 32s	Docker mode activated.
		_ Prechecks _
+1 💚	dupname	0m 0s	No case conflicting files found.
+1 💚	@author	0m 0s	The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s	The patch appears to include 2 new or modified test files.
		_ trunk Compile Tests _
+1 💚	mvninstall	31m 10s	trunk passed
+1 💚	compile	0m 39s	trunk passed with JDK Ubuntu-11.0.8+10-post-Ubuntu-0ubuntu118.04.1
+1 💚	compile	0m 32s	trunk passed with JDK Private Build-1.8.0_265-8u265-b01-0ubuntu2~18.04-b01
+1 💚	checkstyle	0m 27s	trunk passed
+1 💚	mvnsite	0m 37s	trunk passed
+1 💚	shadedclient	15m 23s	branch has no errors when building and testing our client artifacts.
+1 💚	javadoc	0m 23s	trunk passed with JDK Ubuntu-11.0.8+10-post-Ubuntu-0ubuntu118.04.1
+1 💚	javadoc	0m 20s	trunk passed with JDK Private Build-1.8.0_265-8u265-b01-0ubuntu2~18.04-b01
+0 🆗	spotbugs	1m 21s	Used deprecated FindBugs config; considering switching to SpotBugs.
+1 💚	findbugs	1m 19s	trunk passed
		_ Patch Compile Tests _
+1 💚	mvninstall	0m 33s	the patch passed
+1 💚	compile	0m 35s	the patch passed with JDK Ubuntu-11.0.8+10-post-Ubuntu-0ubuntu118.04.1
+1 💚	javac	0m 35s	the patch passed
+1 💚	compile	0m 29s	the patch passed with JDK Private Build-1.8.0_265-8u265-b01-0ubuntu2~18.04-b01
+1 💚	javac	0m 29s	the patch passed
-0 ⚠️	checkstyle	0m 21s	hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core: The patch generated 5 new + 46 unchanged - 5 fixed = 51 total (was 51)
+1 💚	mvnsite	0m 34s	the patch passed
+1 💚	whitespace	0m 0s	The patch has no whitespace issues.
+1 💚	xml	0m 1s	The patch has no ill-formed XML file.
+1 💚	shadedclient	14m 22s	patch has no errors when building and testing our client artifacts.
+1 💚	javadoc	0m 18s	the patch passed with JDK Ubuntu-11.0.8+10-post-Ubuntu-0ubuntu118.04.1
+1 💚	javadoc	0m 16s	the patch passed with JDK Private Build-1.8.0_265-8u265-b01-0ubuntu2~18.04-b01
+1 💚	findbugs	1m 21s	the patch passed
		_ Other Tests _
-1 ❌	unit	6m 56s	hadoop-mapreduce-client-core in the patch passed.
+1 💚	asflicense	0m 35s	The patch does not generate ASF License warnings.
		79m 47s

Reason	Tests
Failed junit tests	hadoop.mapreduce.lib.output.TestFileOutputCommitter

Subsystem	Report/Notes
Docker	ClientAPI=1.40 ServerAPI=1.40 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-2320/2/artifact/out/Dockerfile
GITHUB PR	#2320
JIRA Issue	MAPREDUCE-7282
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient findbugs checkstyle xml
uname	Linux c7c8c7422a2c 4.15.0-60-generic #67-Ubuntu SMP Thu Aug 22 16:55:30 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 83c7c2b
Default Java	Private Build-1.8.0_265-8u265-b01-0ubuntu2~18.04-b01
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.8+10-post-Ubuntu-0ubuntu118.04.1 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_265-8u265-b01-0ubuntu2~18.04-b01
checkstyle	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-2320/2/artifact/out/diff-checkstyle-hadoop-mapreduce-project_hadoop-mapreduce-client_hadoop-mapreduce-client-core.txt
unit	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-2320/2/artifact/out/patch-unit-hadoop-mapreduce-project_hadoop-mapreduce-client_hadoop-mapreduce-client-core.txt
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-2320/2/testReport/
Max. process+thread count	1572 (vs. ulimit of 5500)
modules	C: hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core U: hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-2320/2/console
versions	git=2.17.1 maven=3.6.0 findbugs=4.0.6
Powered by	Apache Yetus 0.13.0-SNAPSHOT https://yetus.apache.org

This message was automatically generated.

[steveloughran]

checkstyle: indentation

./hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java:593:           if (!fs.delete(committedTaskPath, true)) {: 'if' has incorrect indentation level 11, expected level should be 10. [Indentation]
./hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java:594:             throw new IOException("Could not delete " + committedTaskPath);: 'if' child has incorrect indentation level 13, expected level should be 12. [Indentation]
./hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java:595:           }: 'if rcurly' has incorrect indentation level 11, expected level should be 10. [Indentation]
./hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java:697:          throw new IOException("Could not rename " + previousCommittedTaskPath +: Line is longer than 80 characters (found 81). [LineLength]
./hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java:701:          LOG.warn(attemptId+" had no output to recover.");: 'else' child has incorrect indentation level 10, expected level should be 8. [Indentation]

[steveloughran]

v2 MUST be retained, just need to

• remove as default
• log @ WARN in job setup, using a special log so it can be turned off