[gnome-shell] MonitorConstraint: fix clamping monitor index

[Giovanni Campagna <gcampagna src gnome org>]

commit cbd2188c044679bc0129c67e7c60236a8776967b
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Thu Aug 16 22:12:23 2012 +0200

    MonitorConstraint: fix clamping monitor index
    
    I will test my patches, I promise.

 js/ui/layout.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/layout.js b/js/ui/layout.js
index c833a1b..333b809 100644
--- a/js/ui/layout.js
+++ b/js/ui/layout.js
@@ -83,7 +83,7 @@ const MonitorConstraint = new Lang.Class({
         if (this._primary) {
             monitor = Main.layoutManager.primaryMonitor;
         } else {
-            let index = Math.max(this._index, Main.layoutManager.monitors.length);
+            let index = Math.min(this._index, Main.layoutManager.monitors.length - 1);
             monitor = Main.layoutManager.monitors[index];
         }