Remove SSLv3 from nginx

The default enables SSLv3.

https://github.com/jfryman/puppet-nginx/blob/v0.0.9/manifests/resource/vhost.pp#L53-L54

This is no longer a sensible default: SSLv3 is ancient and now has a
published vulnerability in the design.

http://googleonlinesecurity.blogspot.co.uk/2014/10/this-poodle-bites-exploiting-ssl-30.html

By doing this, we prevent people running IE6 on WinXP lower than SP3
from accessing our service. Unfortunately, security concerns mean that
we need to make this change.
Merge pull request #617 from alphagov/feature/disable-sslv3

Remove SSLv3 from nginx