do not retrieve adapter path from dbus message

do not retrieve adapter path from dbus message

Every where, bluetooth-frwk checks the adapter state before doing an action.
Adapter state is retrieved from parsing dbus message from 'GetManagedObjects' method.
This is only needed to get adapter path from dbus message.
As adapter path is always '/org/bluez/hci0' using Bluez5, define it improves performance.

For example, it fixes a bug in Modello UI when getting default adapter with
bonded devices.

Change-Id: I19e86c0ac269b60773ac3b3e3f62d802ebd40013
Signed-off-by: Corentin Lecouvey <corentin.lecouvey@open.eurogiciel.org>