FIX crash in route search if no route was found

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6727 8aca7d54-2c30-db11-9de9-000461428c89
CODE: do not need to test before setting to true - should speed-up route search a litte

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6728 8aca7d54-2c30-db11-9de9-000461428c89
not action in other players depots but viewing

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6729 8aca7d54-2c30-db11-9de9-000461428c89