Fix mvn checkstyle still failing on autogenerated sources

For some reason the <excludes> tag was ignored. We take a different
approach by forcing checkstyle plugin to consider only the project
source directory

Change-Id: I310d2b5be0f0df8e16b11744d6195db31ee3f35e
diff --git a/tools/package/dependencies/template.pom b/tools/package/dependencies/template.pom
index 1c955af..ce823e9 100644
--- a/tools/package/dependencies/template.pom
+++ b/tools/package/dependencies/template.pom
@@ -195,7 +195,7 @@
                         <logViolationsToConsole>true</logViolationsToConsole>
                         <includeTestSourceDirectory>true</includeTestSourceDirectory>
                         <includeResources>false</includeResources>
-                        <excludes>**/generated-sources/**/*</excludes>
+                        <sourceDirectories>${project.build.sourceDirectory}</sourceDirectories>
                     </configuration>
                 </plugin>
                 <plugin>