exclude coverage module from rat check

Author: sumitjnn

Diff for: pom.xml

@@ -232,6 +232,7 @@
                   <exclude>**/org/apache/hadoop/**</exclude>
                   <!-- exclude resource files-->
                   <exclude>**/resources/**</exclude>
+                  <exclude>delta-coverage/target/**</exclude>
                 </excludes>
               </configuration>
             </execution>