[gnome-shell] extensionSystem: Unset stylesheet file reference when unloaded

[Marco Trevisan <marcotrevi src gnome org>]

commit 72f5802be93648429c6d9d586c427c8cfd9ccde2
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri Aug 3 18:19:14 2018 +0200

    extensionSystem: Unset stylesheet file reference when unloaded
    
    We must remove the GFile reference from the representing object when an
    extension has been unloaded as this won't be used anymore later (e.g. as cached
    ref).

 js/ui/extensionSystem.js | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/js/ui/extensionSystem.js b/js/ui/extensionSystem.js
index 6611b5a63..a7a3d2014 100644
--- a/js/ui/extensionSystem.js
+++ b/js/ui/extensionSystem.js
@@ -76,6 +76,7 @@ function disableExtension(uuid) {
     if (extension.stylesheet) {
         let theme = St.ThemeContext.get_for_stage(global.stage).get_theme();
         theme.unload_stylesheet(extension.stylesheet);
+        delete extension.stylesheet;
     }
 
     try {