[Freeciv-Dev] Fixing: do not allow to buy Capitalization.

[rizos@xxxxxxxx]

1. Disabling the buy button when a city is building Capitalization:

Line 978 in client/citydlg.c (inside city_dialog_update_building)
which looks like:

  XtSetSensitive(pdialog->buy_command, !pcity->did_buy);

should look like:

  XtSetSensitive(pdialog->buy_command, (!pcity->did_buy)&&
                    (pcity->currently_building!=B_CAPITAL) );



2. Also the following is needed in case that the AI attempts
   to buy Capitalization:

Lines 416-417 in server/cityhand.c (inside really_handle_city_buy)
which look like:

  if (!pcity->is_building_unit) { 
    total=improvement_value(pcity->currently_building);

should look like:

  if (!pcity->is_building_unit) { 
    if (pcity->currently_building == B_CAPITAL)  return; 
    total=improvement_value(pcity->currently_building);