YARN-5300. Exclude generated federation protobuf sources from YARN Javadoc/findbugs build

(cherry picked from commit 9d23570172ae7984f894406dfc6ad066648c61f4)

hadoop-yarn-project/hadoop-yarn/dev-support/findbugs-exclude.xml

@@ -20,6 +20,9 @@
   <Match>
     <Package name="org.apache.hadoop.yarn.proto" />
   </Match>
+  <Match>
+    <Package name="org.apache.hadoop.yarn.federation.proto" />
+  </Match>
   <Match>
     <Class name="~org\.apache\.hadoop\.yarn\.ipc\.RpcProtos.*" />
   </Match>

hadoop-yarn-project/hadoop-yarn/pom.xml

@@ -75,7 +75,7 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-javadoc-plugin</artifactId>
         <configuration>
-          <excludePackageNames>org.apache.hadoop.yarn.proto</excludePackageNames>
+          <excludePackageNames>org.apache.hadoop.yarn.proto:org.apache.hadoop.yarn.federation.proto</excludePackageNames>
         </configuration>
       </plugin>
     </plugins>