[MCHECKSTYLE-205] NPE in CheckstyleReportGenerator.doFilesSummary:654 version 2.11 regression
Submitted by: Bob Fields
Reviewed by: Dennis Lundberg

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1570752 13f79535-47bb-0310-9956-ffa450edef68