Fix cvs-usage entry. Add it if the repository element is defined in the pom (and not if the URL of the repository is defined)

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@180039 13f79535-47bb-0310-9956-ffa450edef68

xdoc/src/plugin-resources/navigation.jelly

@@ -53,8 +53,8 @@
                             bundle="plugin-resources/templates/templates"
                             href="/dependencies.html" />
 
-                        <j:set var="url" value="${pom.repository.url}" />
-                        <j:if test="${!empty(url)}">
+                        <j:set var="repository" value="${pom.repository}" />
+                        <j:if test="${!empty(repository)}">
                             <item key="navigation.menu.item.source_repository"
                                 bundle="plugin-resources/templates/templates"
                                 href="/cvs-usage.html" />