repair: make paths in "_bundle()" relative to ".hg" This patch makes paths below in "_bundle()" relative to ".hg": - backup directory ("strip-backup"), and - bundle file under backup directory "vfs" is passed to "changegroup.writebundle()" to use relative path directly. This patch applies "vfs.join()" on the value returned by "_bundle()", because the caller expect it to return absolute path. This will be changed by succeeding patch changing the caller side.