Bluetooth: Fix keeping the command timer running

In the teardown path the reset command is sent to the controller,
this event causes the command timer to be reactivated.

So the timer is removed in two situations, when the adapter isn't
marked as UP and when we know that some command has been sent.

Reported-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>