[Ferm] Inaccuracy about subchain concept

[Gian Piero Carrubba]

* [Fri, Jul 26, 2013 at 10:12:12PM +0200] Gian Piero Carrubba:
>Please don't, this is an actual bug that need to be fixed.
>Confirmed with ferm 2.2.

It appears to be intentional:

  2244                 if (exists $rule{protocol}) {
  2245                     $inner{protocol} = $rule{protocol};
  2246                     append_option(%inner, 'protocol', $inner{protocol});
  2247                 }

but I still lack to see the need of special-ruling `proto' when there's 
no need for it (i.e. when no `sport', `dport' or a similar one is used 
inside the subchain).

Ciao,
Gian Piero.