Fix deregister of event on scan closing
Fix deregister of event on scan closing

jeoffman/EDDiscovery,vendolis/EDDiscovery,vendolis/EDDiscovery,jgoode/EDDiscovery,mwerle/EDDiscovery,jeoffman/EDDiscovery,jthorpe4/EDDiscovery,jgoode/EDDiscovery,mwerle/EDDiscovery