[gnome-shell] ScreenShield: make .lock() and .unlock() idempotent

[Giovanni Campagna <gcampagna src gnome org>]

commit 8dc9ceb2bcb1511f77c3e457dbbd775b70ab2a5c
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Fri Aug 17 19:08:17 2012 +0200

    ScreenShield: make .lock() and .unlock() idempotent
    
    Those methods can be called multiple times in certain situations,
    and will be even more so after hooking them to the system bus.

 js/ui/screenShield.js |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/js/ui/screenShield.js b/js/ui/screenShield.js
index f375417..c4a23b6 100644
--- a/js/ui/screenShield.js
+++ b/js/ui/screenShield.js
@@ -616,11 +616,13 @@ const ScreenShield = new Lang.Class({
 
         this._lightbox.hide();
 
-        Main.popModal(this.actor);
-        this.actor.hide();
+        if (this._isModal) {
+            Main.popModal(this.actor);
+            this._isModal = false;
+        }
 
-        this._isModal = false;
         this._isLocked = false;
+        this.actor.hide();
 
         this.emit('lock-status-changed', false);
     },