[gnome-shell/gnome-3-24] panel: Fix a JS warning

[Florian Müllner <fmuellner src gnome org>]

commit 363d35a3eb626964933bb4abdaa2f8762df97aea
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Jun 13 04:46:37 2017 +0200

    panel: Fix a JS warning
    
    We need to track the open-status of indicator menus, but don't want
    to hook up signals more than once, so we check for the handler ID
    we store on the object. As the property is only defined once we did
    set up the signal connection, this check now logs a warning. We
    can avoid it by checking for the existence of the property rather
    than a particular value.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=781471

 js/ui/panel.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/panel.js b/js/ui/panel.js
index fe3fc39..55b9dc9 100644
--- a/js/ui/panel.js
+++ b/js/ui/panel.js
@@ -1104,7 +1104,7 @@ const Panel = new Lang.Class({
     },
 
     _onMenuSet: function(indicator) {
-        if (!indicator.menu || indicator.menu._openChangedId > 0)
+        if (!indicator.menu || indicator.menu.hasOwnProperty('_openChangedId'))
             return;
 
         indicator.menu._openChangedId = indicator.menu.connect('open-state-changed',