Small cleanup of property.c
Small cleanup of property.c

malloch/libmapper,libmapper/libmapper,malloch/libmapper,libmapper/libmapper,libmapper/libmapper,malloch/libmapper,radarsat1/libmapper,malloch/libmapper,libmapper/libmapper,libmapper/libmapper,malloch/libmapper,radarsat1/libmapper,radarsat1/libmapper,radarsat1/libmapper,libmapper/libmapper,radarsat1/libmapper,malloch/libmapper