Consider making Ftp/computePath method protected

[anvaya]

For the adapter classes, the access control varies by the adapter. The Local adapter as computePath method as protected, while the Ftp adapter class has computePath private.

This has made it impossible to override methods such as Read without modifying the access of base Ftp adapter methods to protected to be able to call methods such as computePath.

I implemented custom read method for the FTP adapter to stream the file directly to the browser without first downloading it on the server, ended up modifying the base ftp class methods to protected.