Bug fix in service_machgen_invoke about protobuf-c HOT 2 CLOSED

I think it is correct as written.  machgen has type:
  struct _ServiceMachgen
  {
    ProtobufCService base;
    void *service;
  };
where 'service' is the generated service method table.  Basically, it's type is 
an
array of GenericHandler (the array is represented with GenericHandler*).

If we took a reference, then handlers[0] would be "service" itself, not a 
function
pointer, and your program will crash when it invokes that.

(At the moment, this code is untested, so there may be some bugs... but i don't 
think
this is one)

i was wrong.  your suggestion is correct, but I will commit something slightly
different... namely, I will get rid of ServiceMachgen altogether and use:

  handlers = (GenericHandler *) (service + 1);

(It turns out that there was another related bug a few lines down too: invoking 
the
handler with machgen->service wasn't right..)

This is committed to subversion, will be in 0.8 release, whenever that happens.