add a better default value

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1442911 13f79535-47bb-0310-9956-ffa450edef68
use StringUtils.isNotBlank

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1442912 13f79535-47bb-0310-9956-ffa450edef68