Client-Side SSL with Intermediate Certificates

I have a self signed root certificate and an intermediate certificate signed by that root. Basically something like this:

.
└── master (CA)
    └── servant1 (CA)

I have some client certificates from master->servant1certificate chain :

.
└── master (CA)
    └── servant1 (CA)
        ├── client1
        ├── client2
        └── client3

I'm trying to authenticate these client certificates in nginx and I'm having trouble doing so.

Here is my nginx configuration:

upstream luci {
    server localhost:8080;
}

server {
    listen                  127.0.0.1:80;
    server_name             myserver;

    return 301 https://$host$request_uri;
}

server {
    listen                  127.0.0.1:443;
    server_name             myserver;

    ssl                     on;
    ssl_certificate         /etc/nginx/certs/myserver.crt;
    ssl_certificate_key     /etc/nginx/certs/myserver.key;

    ssl_session_timeout 5m;

    ssl_prefer_server_ciphers on;
    ssl_protocols TLSv1.2 TLSv1.1;
    ssl_ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:RSA+AES:!ECDH+3DES:!DH+3DES:!RSA+3DES:!aNULL:!MD5:!DSS;

    ssl_client_certificate /etc/nginx/certs/servant1-ca-chain.crt;
    ssl_verify_client on;
    ssl_verify_depth 2;

    location / {
        proxy_pass http://luci;
    }
}

This should be simple. All client certificates signed by intermediate CAs servant1should be allowed to connect to nginx.

However, when I try to access the server with these client certificates, I get the following:

^{(obviously a very detailed and useful bug)}

I found this in the log:

2013/12/01 22:46:18 [alert] 7478#0: *5 ignoring stale global SSL error (SSL: error:0407006A:lib(4):func(112):reason(106) error:04067072:lib(4):func(103):reason(114) error:0D0C5006:lib(13):func(197):reason(6)) while reading client request line, client: 192.168.1.208, server: myserver

Useful information is:

Ignore outdated global SSL errors

What's wrong and how can I fix it?