content.json not distributed after OK publish

### Step 1: Please describe your environment

* ZeroNet version: 0.6.0 - rev 3171
* Operating system: Linux/ubuntu 16.04
* Web browser: Chrome 62.0.3202.94 (64 bits)
* Tor status: error
* Opened port: no
* Special configuration: ____

### Step 2: Describe the problem:
11:37:38.768 JS: sitePublish OK. elapsed time for sitrePublish 169 ms. Very short time for a sitePublish request!!! sitePublish response should have been about 8 seconds. Se below.
11:37:38 UI server: RateLimit Added to queue (12.96s left)
11:37:38.903 JS: siteSign OK
11:37:46 UI server content.json published to 1 peers, publishing to 5 more peers in the background
The content.json file published at 11:37:38.768 was never distributed on ZeroNet.

#### Steps to reproduce:

Have only seen this problem once. Maybe hard to reproduce:
1. sitePublish with RateLimit added to queue in UI server log
2. siteSign

#### Observed Results:

* content.json file was not distributed on ZeroNet

#### Expected Results:

* content.json file to be distributed after OK publish

[issue262-test11-w2-torando.log](https://github.com/HelloZeroNet/ZeroNet/files/1565767/issue262-test11-w2-torando.log)
[issue262-test11-ui-torando.log](https://github.com/HelloZeroNet/ZeroNet/files/1565768/issue262-test11-ui-torando.log)

Start with the attached issue262-test11-w2-torando.log and issue262-test11-ui-torando.log, tracing the sitePublish and siteSign sequence when RateLimit is queued. Reproduce the reported ordering if possible and inspect the publish and distribution entry points. Done means content.json published after an OK publish is distributed to peers reliably.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.