AMBARI-22875. Exclude generated sources from checkstyle (#512)

ambari-project/pom.xml

@@ -515,7 +515,10 @@
             <encoding>UTF-8</encoding>
             <consoleOutput>true</consoleOutput>
             <failsOnError>true</failsOnError>
-            <includeTestSourceDirectory>true</includeTestSourceDirectory>
+            <sourceDirectories>
+              <sourceDirectory>src/main/java</sourceDirectory>
+              <sourceDirectory>src/test/java</sourceDirectory>
+            </sourceDirectories>
             <linkXRef>false</linkXRef>
           </configuration>
           <executions>