a typo in default variable of nginx_source_modules_included

The name `http_real_ip_module` https://github.com/ANXS/nginx/blob/master/defaults/main.yml#L82
does not match with `http_realip_module` in tasks/modules.yml https://github.com/ANXS/nginx/blob/master/tasks/modules.yml#L31

solution:

in the file `default/main.yml`

replace

```
http_real_ip_module: "--with-http_realip_module"
```

with

```
http_realip_module: "--with-http_realip_module"
```
