simgraph0.cc finallz fixed also for multithreading

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6792 8aca7d54-2c30-db11-9de9-000461428c89
simgraph0.cc finallz fixed also for single threading

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6793 8aca7d54-2c30-db11-9de9-000461428c89