'Make the tmp new key a valid new key.
The tmp new key must be created by _create_tmp_new_key().'

def _become_valid_new_key(self):

    tmp_key_file = os.path.join(self.key_repository, '0.tmp')
    valid_key_file = os.path.join(self.key_repository, '0')
    os.rename(tmp_key_file, valid_key_file)
    LOG.info('Become    a    valid    new    key:    %s', valid_key_file)
