ensure maven.docs.outputencoding is taken from xdoc plugin

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@113642 13f79535-47bb-0310-9956-ffa450edef68

checkstyle/plugin.jelly

@@ -147,6 +147,8 @@
 
       </ant:checkstyle>
       
+      <j:set var="maven.docs.outputencoding" value="${pom.getPluginContext('maven-xdoc-plugin').getVariable('maven.docs.outputencoding')}"/>
+      
       <doc:jsl
         input="${maven.build.dir}/checkstyle-raw-report.xml"
         output="checkstyle-report.xml"