MAVEN-243: Test xref doesn't have a javadoc link

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@112842 13f79535-47bb-0310-9956-ffa450edef68

jxr/plugin.jelly

@@ -75,7 +75,7 @@
       sourceDir="${pom.build.unitTestSourceDirectory}"
       destDir="${maven.jxr.destdir}"
       templateDir="${maven.jxr.templateDir}"
-      javadocDir="${javadocDestdir}"
+      javadocDir="${null}"
       windowTitle="${title}"
       docTitle="${title}"
       bottom="${copyright}">