Authenticate a user by the token specified in load.
        Return the token object or False if auth failed.

def authenticate_token(self, load):
        '''
        Authenticate a user by the token specified in load.
        Return the token object or False if auth failed.
        '''
        token = self.get_tok(load['token'])

        # Bail if the token is empty or if the eauth type specified is not allowed
        if not token or token['eauth'] not in self.opts['external_auth']:
            log.warning('Authentication failure of type "token" occurred.')
            return False

        return token