Attempt to reuse the application if it's already running

pkg/dashboard/static/scripts.js

@@ -17,7 +17,7 @@ $(function () {
     $.getJSON("/api/scanners").fail(function (xhr) {
         reportError("Failed to get list of scanners", xhr)
     }).done(function (data) {
-        if (!data.length) {
+        if (!data || !data.length) {
             $("#upgradeModal .btn-scan").hide()
         }
     })