Code review comment for lp:~ed.so/duplicity/lftp.ncftp.and.prefixes

I like the general cleanup.

A couple of changes:

Please leave the file naming as it was. I had set these to be underscore-first to show they were called by the main ssh backend. See _boto*, _cf*.

I would like to see sftp: and scp: protocols go away. In reality they are just subsets of the OpenSSH (or other) package. You really can't run just scp: since we need 'ls' and 'del'. If we continue to allow these we need to emphasize that these are just aliases for ssh:.