set the value to something to make this field non-null all the time.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@11396 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/Hudson.java

@@ -2586,7 +2586,7 @@ public final class Hudson extends View implements ItemGroup<TopLevelItem>, Node,
     /**
      * Version number of this Hudson.
      */
-    public static String VERSION;
+    public static String VERSION="?";
 
     /**
      * Prefix to static resources like images and javascripts in the war file.