fails with curl > 8.17.0 after removal of Kerberos support

Description:

libcurl 8.17.0 dropped support for Kerberos FTP, which results in thecurl_easy_setopt_or_die(..., CURLOPT_KRB4LEVEL, ...) call failing with an inscrutable message.

Additional info:

Steps to reproduce:

Use curlftpfs with any configuration:

curlftpfs ftp.example.com /some/dir