[gnome-shell] shellDBus: Fix Eval() return value when disabled

[Florian Müllner <fmuellner src gnome org>]

commit 39426f03e62d859f511448785516516d0f3e50c2
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Apr 26 15:17:11 2013 +0200

    shellDBus: Fix Eval() return value when disabled
    
    Eval() is expected to return a boolean success value and a string result.
    However when the function is disabled (via the development-tools setting),
    we return null for the latter which is not a valid string value.
    Return an empty string instead.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=698959

 js/ui/shellDBus.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/shellDBus.js b/js/ui/shellDBus.js
index 727792c..12e4b84 100644
--- a/js/ui/shellDBus.js
+++ b/js/ui/shellDBus.js
@@ -97,7 +97,7 @@ const GnomeShell = new Lang.Class({
      */
     Eval: function(code) {
         if (!global.settings.get_boolean('development-tools'))
-            return [false, null];
+            return [false, ''];
 
         let returnValue;
         let success;