Fix a couple of coffee to js conversion blunders

lib/db.js

@@ -831,7 +831,7 @@ function getDueTasks(deviceId, timestamp, callback) {
           if (res[0]) {
             if (!task.fileType) task.fileType = res[0].metadata.fileType;
 
-            if (task.fileName)
+            if (!task.fileName)
               task.fileName = res[0].filename || res[0]._id.toString();
           }