Marvin test: exclude sandbox.cfg from the rat check

pom.xml

diff --git a/pom.xml b/pom.xml
index 9dbd1bf..e8fdb2f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -437,6 +437,7 @@
               <exclude>patches/systemvm/debian/config/var/www/html/latest/.htaccess</exclude>
               <exclude>patches/systemvm/debian/vpn/etc/ipsec.d/l2tp.conf</exclude>
               <exclude>tools/transifex/.tx/config</exclude>
+              <exclude>tools/marvin/marvin/sandbox/advanced/sandbox.cfg</exclude>
             </excludes>
           </configuration>
         </plugin>