[gnome-shell/wip/rstrode/rhel-7.9: 34/86] system: don't throw an exception if power off disabled

[Ray Strode <halfline src gnome org>]

commit c2033d66ed5ab1352804b79635a19e8007e18f51
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Jun 4 13:48:02 2018 -0400

    system: don't throw an exception if power off disabled

 js/ui/status/system.js | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)
---
diff --git a/js/ui/status/system.js b/js/ui/status/system.js
index 68a0b4b5b9..2ab38419f6 100644
--- a/js/ui/status/system.js
+++ b/js/ui/status/system.js
@@ -67,12 +67,15 @@ var AltSwitcher = new Lang.Class({
                     childShown.fake_release();
                 childShown.remove_action(this._clickAction);
             }
-            childToShow.add_action(this._clickAction);
 
-            let hasFocus = this.actor.contains(global.stage.get_key_focus());
-            this.actor.set_child(childToShow);
-            if (hasFocus)
-                childToShow.grab_key_focus();
+            if (childToShow) {
+                childToShow.add_action(this._clickAction);
+
+                let hasFocus = this.actor.contains(global.stage.get_key_focus());
+                this.actor.set_child(childToShow);
+                if (hasFocus)
+                    childToShow.grab_key_focus();
+            }
 
             // The actors might respond to hover, so
             // sync the pointer to make sure they update.