Updating some more plugins that were referring to maven.docs.dest

property from the xdoc plugin.  These have been updated to use the new
method of accessing properties in other plugins.  While cleaning this
up, I also noticed a handful of other repetitive properties in
plugin.properties files, which I also removed/cleaned.


git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@112744 13f79535-47bb-0310-9956-ffa450edef68

jdiff/plugin.jelly

@@ -8,12 +8,15 @@
       
   <goal
     name="jdiff"
+    prereqs="xdoc:init"
     description="generate an api difference report between versions">
 
     <property name="maven.jdiff.dir" value="${maven.build.dir}/jdiff"/>
     <mkdir dir="${maven.jdiff.dir}"/>
 
-    <property name="maven.jdiff.changes.dir" value="${maven.docs.dest}/jdiff"/>    
+    <j:set var="docsDest"
+      value="${pom.getPluginContext('maven-xdoc-plugin').getVariable('maven.docs.dest')}"/>
+    <property name="maven.jdiff.changes.dir" value="${docsDest}/jdiff"/>    
     <mkdir dir="${maven.jdiff.changes.dir}"/>
             
     <condition property="maven.jdiff.new.current" value="true">