fixing typo, refs #22

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@16103 29f149b2-0c63-11e1-8f5c-a347f6a9acd0
extracting districts from polys

git-svn-id: http://svn.code.sf.net/p/sumo/code/trunk/sumo@16104 29f149b2-0c63-11e1-8f5c-a347f6a9acd0