modified to display the plugin version number.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1939 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/PluginWrapper.java

@@ -270,6 +270,15 @@ public final class PluginWrapper {
         return shortName;
     }
 
+    /**
+     * Returns the version number of this plugin
+     */
+    public String getVersion() {
+        String v = manifest.getMainAttributes().getValue("Plugin-Version");
+        if(v!=null)      return v;
+        return "???";
+    }
+
     /**
      * Gets the "abc" portion from "abc.ext".
      */