Do not upward ENOENT from storaged up to the application
When a file has never been written on disk but a read is requested
the storio responds to the storcli with a ENOENT errno. This code
is taken into account in the storcli internal read request as if the
file is empty. In case of the read request comming from VFS, the ENOENT
should be returned withh no error but a zero length data buffer.