[HUDSON-4562] keep / in zip link if glob pattern is nonempty

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@23603 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/resources/hudson/model/DirectoryBrowserSupport/dir.jelly

@@ -87,7 +87,7 @@ THE SOFTWARE.
               <tr>
                 <td style="text-align:right;" colspan="3">
                   <div style="margin-top: 1em;">
-                    <a href="${backPath}${pattern}*zip*/${dir.name}.zip">
+                    <a href="${backPath}${pattern!=''?pattern+'/':''}*zip*/${dir.name}.zip">
                       <img src="${imagesURL}/16x16/package.gif"/>
                       (${%all files in zip})
                     </a>