Fix invalid reference to fileNameFromKey

src/app/storage-handler.js

@@ -16,7 +16,7 @@ function StorageHandler (updateFiles) {
     function check (key) {
       chrome.storage.sync.get(key, function (resp) {
         console.log('comparing to cloud', key, resp);
-        if (typeof resp[key] !== 'undefined' && obj[key] !== resp[key] && confirm('Overwrite "' + fileNameFromKey(key) + '"? Click Ok to overwrite local file with file from cloud. Cancel will push your local file to the cloud.')) {
+        if (typeof resp[key] !== 'undefined' && obj[key] !== resp[key] && confirm('Overwrite "' + utils.fileNameFromKey(key) + '"? Click Ok to overwrite local file with file from cloud. Cancel will push your local file to the cloud.')) {
           console.log('Overwriting', key);
           localStorage.setItem(key, resp[key]);
           updateFiles();