[merge] remove SFTPLock and support for weaves over SFTP

[Bundle Buggy]

Bundle Buggy has detected this merge request.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3Ce01316480901260947t46feb8d6n7ba57b0788a0ae7e%40mail.gmail.com%3E
Project: Bazaar