Bug+bugfix in sftp-server : failed to rename file on sshfs mount

[Johan Kielbaey]

Hello,

Renaming a file via sftp on an sshfs mount resulted in a failure with
errorcode 38 (ENOSYS).

This is reproducable with openssh release 4.9p1 & 5.1p1 in combination
sshfs 2.2 (latest releases). Investigation revealed that sshfs only
implements the rename()-call and not the link()-call (used by
sftp-server).

Attached is a patch to perform the rename()-call upon a failed link().
The patch is against openssh-5.1p1.

Kind regards,

Johan