Extract the images dir from the configuration. First attempts to
    find legacy virt.images, then tries virt:images.

def _get_images_dir():
    '''
    Extract the images dir from the configuration. First attempts to
    find legacy virt.images, then tries virt:images.
    '''
    img_dir = __salt__['config.option']('virt.images')
    if img_dir:
        salt.utils.versions.warn_until(
            'Sodium',
            '\'virt.images\' has been deprecated in favor of '
            '\'virt:images\'. \'virt.images\' will stop '
            'being used in {version}.')
    else:
        img_dir = __salt__['config.get']('virt:images')

    log.debug('Image directory from config option `virt:images`'
              ' is %s', img_dir)
    return img_dir