sftp-server advertises fstatvfs@openssh.com even though it is not supported

[rtollert]

fstatvfs is not (currently) implemented on win32, but it's still advertised in SSH_FXP_INIT. I'd be OK with simply not advertising this as a supported extension.

[bagajjal]

@rtollert - Thanks for reporting. This will be fixed in next release.

[WSLUser]

I'd prefer it to be implemented over ignoring it if possible. The more openssh features we have on Windows, the better.