Bluetooth: Fix bt_conn_lookup_addr_le and bt_conn_lookup_handle

bt_conn_lookup_addr_le shouldn't look for the state of the connection.
bt_conn_lookup_handle should return bt_conn only if there is a handle
so if connection is in state BT_CONN_CONNECTED or BT_CONN_DISCONNECT.

Change-Id: Id88361990913d17bdaffc686e5aa3edaeaaecc0a
Signed-off-by: Mariusz Skamra <mariusz.skamra@tieto.com>