bluetooth: Fix possible adapter duplicates
The D-Bus signal AdapterAdded can be received during our call to
GetProperties(), before the reply is received. In this case, the adapter
will be listed twice and thus the endpoint registration will fail with
"AlreadyExists" as follows:
D: [pulseaudio] bluetooth-util.c: dbus: interface=org.bluez.Manager, path=/, member=AdapterAdded
D: [pulseaudio] bluetooth-util.c: Adapter /org/bluez/21220/hci0 created
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/HFPAG on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/HFPHS on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/A2DPSource on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/A2DPSink on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/HFPAG on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/HFPHS on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/A2DPSource on adapter /org/bluez/21220/hci0.
D: [pulseaudio] bluetooth-util.c: Registering /MediaEndpoint/A2DPSink on adapter /org/bluez/21220/hci0.
E: [pulseaudio] bluetooth-util.c: RegisterEndpoint() failed: org.bluez.Error.AlreadyExists: Already Exists
E: [pulseaudio] bluetooth-util.c: RegisterEndpoint() failed: org.bluez.Error.AlreadyExists: Already Exists
E: [pulseaudio] bluetooth-util.c: RegisterEndpoint() failed: org.bluez.Error.AlreadyExists: Already Exists
E: [pulseaudio] bluetooth-util.c: RegisterEndpoint() failed: org.bluez.Error.AlreadyExists: Already Exists