kete: make Searcher and Listener symmetrical regarding logs

The 'searching' notification was only emitted when it goes to stop, which
means we do not get notifications when it starts.
This makes SearchStopped signal redundant for the generic case, but allows
to get notifications if the search failed to start.

Rest is just making sure we have the same handling of events in Listener
and Searcher.

tools/tuhi-kete.py

@@ -346,6 +346,8 @@ class TuhiKeteManager(_DBusObject):
                     # in unregistered devices
                     pass
             self.notify('devices')
+        if 'Searching' in changed_props:
+            self.notify('searching')
 
     def _handle_unregistered_device(self, objpath):
         for addr, dev in self._devices.items():
@@ -418,8 +420,8 @@ class Searcher(Worker):
             logger.error('Another client is already searching')
             return
 
+        logger.debug(f'Starting searching')
         self.manager.start_search()
-        logger.debug('Started searching')
 
     def stop(self):
         if self.manager.searching:
@@ -432,6 +434,8 @@ class Searcher(Worker):
         if not manager.searching:
             logger.info('Search cancelled')
             self.stop()
+        else:
+            logger.info('Search started')
 
     def _on_unregistered_device(self, manager, device):
         logger.info(f'Unregistered device: {device}')
@@ -471,8 +475,9 @@ class Listener(Worker):
         self.device.start_listening()
 
     def stop(self):
-        logger.debug(f'{self.device}: stopping listening')
-        self.device.stop_listening()
+        if self.device.listening:
+            logger.debug(f'{self.device}: stopping listening')
+            self.device.stop_listening()
 
         self.cleanup()