update failed

### Step 1: Please describe your environment

* ZeroNet version: 0.6.2（3408）
* Operating system: _windows 10 1803
* Web browser: Firefox 59.0.3 x64
* Tor status: disabled
* Opened port: no
* Special configuration: no

### Step 2: Describe the problem:

#### Steps to reproduce:

1. blog always update failed
2. storage limitation have been set 9999 mb

#### Observed Results:

* What happened? This could be a screenshot, a description, log output (you can send log/debug.log file to hello@zeronet.io if necessary), etc.

#### Expected Results:

* What did you expect to happen?