HADOOP-17309. Javadoc warnings and errors are ignored in the precommit jobs. (#2391)

(cherry picked from commit 3a0922fb4207af2f06f8ef57e83ff9759871d0cb)

 Conflicts:
	hadoop-project/pom.xml

hadoop-project/pom.xml

@@ -1370,6 +1370,7 @@
           <artifactId>maven-javadoc-plugin</artifactId>
           <version>${maven-javadoc-plugin.version}</version>
           <configuration>
+            <doclint>all</doclint>
             <additionalparam>-Xmaxwarns 10000</additionalparam>
           </configuration>
         </plugin>