remove incorrect -R from chown in samba directory set up, as it changed ...

...existing rom files. Now we correctly

set root:$user for roms with the sticky bit set, with first level platform subfolders being root:$pi with group writable.
added some code to chown existing files to fix any set up where roms were copied with the wrong permissions.
there are other cases too, where roms are copied with the wrong permissions which this will fix, such as the install_zmachine
code which unpacks files as the root user

#387