Correctly initialize attribution aria state
Correctly initialize attribution aria state

Co-authored-by: Marc Jansen <af3a4f12ca527d012127cd060074a4c3348cdbc2@terrestris.de>
ahocevar/ol3,openlayers/openlayers,ahocevar/ol3,stweil/ol3,ahocevar/ol3,stweil/openlayers,ahocevar/openlayers,bjornharrtell/ol3,stweil/openlayers,bjornharrtell/ol3,oterral/ol3,adube/ol3,oterral/ol3,adube/ol3,adube/ol3,stweil/ol3,openlayers/openlayers,stweil/openlayers,ahocevar/ol3,bjornharrtell/ol3,openlayers/openlayers,oterral/ol3,stweil/ol3,ahocevar/openlayers,stweil/ol3,ahocevar/openlayers