[FIXED JENKINS-17508] Artifacts not being deleted by LogRotator

previous pull request had merge issues according to jenkins, but it's not behind anything

as per comment https://issues.jenkins-ci.org/browse/JENKINS-17508?focusedCommentId=177275&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-177275 it seems to be a working fix