pagekite: Don't update names module if not installed

- Due to a minor regression with init() method refactoring:

  - Pagekite tries to check if it is enabled even when it is not installed. This
  is an unnecessary check.

  - Pagekite tries to remove domains from name services even when it is not
  installed. This could have unnecessary consequences.

Fix this by checking if Pagekite is installed and perform name services updating
only if service is enabled.

Tests:

- Enable pagekite and configure it. When FreedomBox is restarted, Pagekite kite
is announced as domain and shown in Name Services.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/pagekite/__init__.py

@@ -81,7 +81,9 @@ class PagekiteApp(app_module.App):
         self.add(daemon)
 
         # Register kite name with Name Services module.
-        utils.update_names_module(is_enabled=self.is_enabled())
+        setup_helper = globals()['setup_helper']
+        if setup_helper.get_state() != 'needs-setup' and self.is_enabled():
+            utils.update_names_module(is_enabled=True)
 
     def enable(self):
         """Send domain signals after enabling the app."""