see #9400 - initialize data file for `source:maxspeed` validation

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6487 0c6e7542-c601-0410-84e7-c038aed88b3b
cleanup in `data` folder

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6488 0c6e7542-c601-0410-84e7-c038aed88b3b