title: 404 Not Found when access html under subdirectory
body: <p>I can not access pages under <code>tw</code> folder</p>
  
  <p>eg: <code>about.html</code></p>
  
  <p>I will got this error <code>404 Not Found</code></p>
  
  <p>But I can access the <code>index.html</code> page</p>
  
  <h2>Nginx conf</h2>
  
  <pre><code>server{
      server_name great.com;
      root /www/gp;
      expires off;
      try_files $uri/index.html /dev/null =404;
  
      location ~* \.(js|jpg|png|css)$ {
          root /www/gp;
          expires 30d;
      }
  
      location /tw/ {
          autoindex on;
          root /www/gp/tw;
      }
  
  }
  </code></pre>
  
  <h2>Folder structure</h2>
  
  <pre><code>.
  ├── index.html
  └── tw
      ├── about.html
      ├── brand01.html
      ├── brand.html
      ├── contact.html
      ├── css
      ├── faq01.html
      ├── faq02.html
      ├── images
      ├── js
      └── news.html
  </code></pre>
  
  <h2>Error log in nginx log</h2>
  
  <pre><code>2014/10/31 12:00:15 [error] 12047#0: *6 open() "/www/gp/tw/tw/images/waves.gif" failed (2: No such file or directory), client: 118.163.149.126, server: great-compassion.com, request: "GET /
  tw/images/waves.gif HTTP/1.1", host: "www.great-compassion.com", referrer: "http://www.great-compassion.com/tw/css/banner.css"
  2014/10/31 12:00:18 [error] 12047#0: *5 open() "/www/gp/tw/tw/brand.html" failed (2: No such file or directory), client: 118.163.149.126, server: great-compassion.com, request: "GET /tw/bra
  nd.html HTTP/1.1", host: "www.great-compassion.com", referrer: "http://www.great-compassion.com/"
  </code></pre>