Allow to pass --add-modules to javadoc as well as we get lots of missing code reported otherwise, we cannot use the existing property java9addmods as we need to use a different default-value for non-JDK9 builds

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1776797 13f79535-47bb-0310-9956-ffa450edef68

build.xml

     <!-- this can be overwriten to empty when running with Java 9 -->
     <property name="maxpermsize" value="-XX:MaxPermSize=256m"/>
     <property name="java9addmods" value="-Dthis.is.a.dummy=true"/>
+    <property name="javadoc9addmods" value="-J-Dthis.is.a.dummy=true"/>
     <property name="java9addmodsvalue" value="-Dthis.is.a.dummy=true"/>
     <property name="java9addopens1" value="-Dthis.is.a.dummy=true"/>
     <property name="java9addopens2" value="-Dthis.is.a.dummy=true"/>
             <packageset dir="${ooxml.src}" defaultexcludes="yes">
                 <include name="org/apache/poi/**"/>
             </packageset>
+            
+            <arg value="${javadoc9addmods}"/>
 
             <doctitle><![CDATA[<h1>POI API Documentation</h1>]]></doctitle>
             <bottom>

jenkins/create_jobs.groovy

     [ name: 'POI-DSL-1.9', jdk: '1.9', trigger: triggerSundays,
         properties: ['-Dmaxpermsize=-Dthis.is.a.dummy=true',
                      '-Djava9addmods=--add-modules=java.xml.bind',
+                     '-Djavadoc9addmods=--add-modules=java.xml.bind',
                      '-Djava9addmodsvalue=-Dsun.reflect.debugModuleAccessChecks=true',
                      '-Djava9addopens1=--add-opens=java.base/com.sun.org.apache.xerces.internal.util=ALL-UNNAMED',
                      '-Djava9addopens2=--add-opens=java.base/java.io=ALL-UNNAMED',