Clear update.lk for all remotes

def clear_lock(self, remote=None, lock_type='update'):
        '''
        Clear update.lk for all remotes
        '''
        cleared = []
        errors = []
        for repo in self.remotes:
            if remote:
                # Specific remote URL/pattern was passed, ensure that the URL
                # matches or else skip this one
                try:
                    if not fnmatch.fnmatch(repo.url, remote):
                        continue
                except TypeError:
                    # remote was non-string, try again
                    if not fnmatch.fnmatch(repo.url, six.text_type(remote)):
                        continue
            success, failed = repo.clear_lock(lock_type=lock_type)
            cleared.extend(success)
            errors.extend(failed)
        return cleared, errors