Fix Cancel button when (un)installing and updating

pardusflatpakgui/installwindow.py

@@ -260,7 +260,7 @@ class InstallWindow(object):
 
     def on_press_cancel(self, button):
         self.InstallCancellation.cancel()
-        self.InstallWindow.hide_on_delete()
+        self.InstallWindow.destroy()
 
     def on_delete_action_window(self, widget, event):
         self.InstallCancellation.cancel()