Back compatible: get pre-existing target BEDs.

def _get_original_targets(data):
    """Back compatible: get pre-existing target BEDs.
    """
    work_dir = os.path.join(_sv_workdir(data), "raw")
    batch = dd.get_batch(data) or dd.get_sample_name(data)
    return (glob.glob(os.path.join(work_dir, "*-%s.target.bed" % batch))[0],
            glob.glob(os.path.join(work_dir, "*-%s.antitarget.bed" % batch))[0])