Following up on my previous patch, I've gone through the ssh.c source
code and made several improvements in error handling:

1. File not found errors now return CURLE_REMOTE_FILE_NOT_FOUND
instead of CURLE_SSH
2. Removed a bunch of carriage returns from failf() calls; I
understand they're not supposed to be there
3. If an SFTP file transfer or directory listing fails for whatever
reason, we call failf() with an English version of the server response
4. SFTP and SCP authentication failures now return CURLE_LOGIN_DENIED
instead of CURLE_FAILED_INIT (because CURLE_FAILED_INIT makes no
sense in this context)

I didn't do it, but I think it would be nice if there were more CURL
error codes for certain transfer failures, e.g. permission denied,
disk full, etc. I see there are a few of these for TFTP specifically,
but they ought to be made generic, so they can be used with FTP,
SFTP, etc.

Nick Zitzmann
<http://www.chronosnet.com/>