Delete the current session
        http://docs.opsview.com/doku.php?id=opsview4.6:restapi#logout

def logout(self, verbose=False):
        '''
        Delete the current session
        http://docs.opsview.com/doku.php?id=opsview4.6:restapi#logout
        '''
        url = '{}/{}'.format(self.rest_url, 'logout')
        response = self.__auth_req_post(url, verbose=verbose)
        self.headers['X-Opsview-Token'] = None
        return response