'Configure the driver for the cache and, if it fails to configure,
fall back to using the SQLite driver which has no odd dependencies'

def configure_driver(self):

    try:
        self.driver = self.driver_class()
        self.driver.configure()
    except exception.BadDriverConfiguration as config_err:
        driver_module = self.driver_class.__module__
        LOG.warn(_LW("Image    cache    driver    '%(driver_module)s'    failed    to    configure.    Got    error:    '%(config_err)s"), {'driver_module': driver_module, 'config_err': config_err})
        LOG.info(_LI('Defaulting    to    SQLite    driver.'))
        default_module = (__name__ + '.drivers.sqlite.Driver')
        self.driver_class = importutils.import_class(default_module)
        self.driver = self.driver_class()
        self.driver.configure()
