Add fs prefix (directory)

This ensures the fs root is clean and does not mess with
the metadata. Also in the future this will allow for multiple
filesystems to be created in one bucket.

pkg/s3/mounter_s3ql.go

@@ -49,7 +49,9 @@ func newS3qlMounter(b *bucket, cfg *Config) (Mounter, error) {
 		ssl:        ssl,
 	}
 
-	url.Path = path.Join(url.Path, b.Name)
+	// s3ql requires a trailing slash or it will just
+	// prepend the fspath to the s3ql files
+	url.Path = path.Join(url.Path, b.Name, b.FSPath) + "/"
 	s3ql.bucketURL = url.String()
 
 	if !ssl {