Require TLS with AES cipher

Disabling the RC4 cipher: the number of clients connecting to our
OpenStack controller node is relatively limited and we can force them to
use a modern cipher. Additionally commenting the cipher configuration so
save referencing the HAProxy configuration manual to ensure we are not
forcing SSLv2.
Merge pull request #118 from blueboxgroup/disable-rc4

Require TLS with AES cipher