Update Docker Registry documentation (TLS/SSL required since 1.9)

[michelkaeser]

Quick'n'dirty until documented:

1. http://serverfault.com/questions/611120/failed-tls-handshake-does-not-contain-any-ip-sans#611121
2. create self-signed SSL cert (see Docker guide)
3. mkdir -p /etc/docker/certs.d/192.168.0.1:5000
   -> copy domain.crt from master into that directory as ca.crt
4. ln -s /etc/docker/certs.d/192.168.0.1:5000/ca.crt /usr/local/share/ca-certificates/192.168.0.1.crt
5. update-ca-certificates
6. service docker stop && service docker start