don't execute this IT with Maven 2.x since configuring rulesets parameter to empty value results to default value instead of empty value

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1550979 13f79535-47bb-0310-9956-ffa450edef68
added comment

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1550980 13f79535-47bb-0310-9956-ffa450edef68