[bluez] Tweak local name queries. Fixes JB#11905.

Having an explicit query for local name when the kernel announces
the name to bluetoothd just as well results in two read local name
query complete events with an empty string for name on adapter
powerup. This may cause D-Bus events for adapter name property
change with the name as empty string.

Such property changes may confuse other modules that act based on
the name property; as our kernel seems to reliable send the local
name without bluetoothd explicitly querying it, fix the issue by
deferring local name query until later. By that time it's probably
been received already from the kernel spontaneously and it's not
necessary to make a query.