更新 Nginx 到 Mainline 版 1.13.1

内容简介：更新 Nginx 到 Mainline 版 1.13.1

使用 Nginx 的 Mainline 版其实已经有很长时间了，我感觉还是很稳定的，性能真的很出众！今天发现 Nginx 的 Mainline 版已经更新到 1.13.1 了，于是就第一时间的更新了 LNMP 里的 Nginx 。

Mainline 版 Nginx 1.13.1 更新日志：

*) Feature: now a hostname can be used as the "set_real_ip_from"

directive parameter.
*) Feature: vim syntax highlighting scripts improvements.
*) Feature: the "worker_cpu_affinity" directive now works on DragonFly
```
BSD.
  Thanks to Sepherosa Ziehau.
```
*) Bugfix: SSL renegotiation on backend connections did not work when
```
using OpenSSL before 1.1.0.
```
*) Workaround: nginx could not be built with Oracle Developer Studio
```
12.5.
```
*) Workaround: now cache manager ignores long locked cache entries when
```
cleaning cache based on the "max_size" parameter.
```

*) Bugfix: client SSL connections were immediately closed if deferred

accept and the "proxy_protocol" parameter of the "listen" directive
  were used.

*) Bugfix: in the "proxy_cache_background_update" directive.
*) Workaround: now the "tcp_nodelay" directive sets the TCP_NODELAY
```
option before an SSL handshake.
```