dbus: don't update self.paired unless it changes

TuhDevice.paired is set on every device update (RSSI changes!) and that sends
a GObject.notify() for the property. Filter those, otherwise
we're just spamming dbus with PropertiesChanged notify events even
though nothing has actually changed.

tuhi/dbusserver.py

@@ -206,6 +206,8 @@ class TuhiDBusDevice(GObject.Object):
         self.emit('pair-requested')
 
     def _on_device_paired(self, device, pspec):
+        if self.paired == device.paired:
+            return
         self.paired = device.paired
 
     def _start_listening(self, connection, sender):