updater: set the backup memory limit

src/tasks.js

@@ -1,20 +1,20 @@
 'use strict';
 
 exports = module.exports = {
-    get: get,
-    add: add,
-    update: update,
-    setCompleted: setCompleted,
-    setCompletedByType: setCompletedByType,
-    listByTypePaged: listByTypePaged,
+    get,
+    add,
+    update,
+    setCompleted,
+    setCompletedByType,
+    listByTypePaged,
 
-    getLogs: getLogs,
+    getLogs,
 
-    startTask: startTask,
-    stopTask: stopTask,
-    stopAllTasks: stopAllTasks,
+    startTask,
+    stopTask,
+    stopAllTasks,
 
-    removePrivateFields: removePrivateFields,
+    removePrivateFields,
 
     // task types. if you add a task here, fill up the function table in taskworker and dashboard client.js
     TASK_APP: 'app',