preserve stack trace

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1199360 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/maven/plugin/pmd/CpdReport.java b/src/main/java/org/apache/maven/plugin/pmd/CpdReport.java
index 968e8b6..ac8dbfd 100644
--- a/src/main/java/org/apache/maven/plugin/pmd/CpdReport.java
+++ b/src/main/java/org/apache/maven/plugin/pmd/CpdReport.java
@@ -276,7 +276,7 @@
             catch ( Exception e )
             {
                 throw new MavenReportException(
-                    "Can't find CPD custom format " + format + ": " + e.getClass().getName() );
+                    "Can't find CPD custom format " + format + ": " + e.getClass().getName(), e );
             }
         }