Disable haproxy http-server-close

This causes haproxy to send 'Connection: close'.
This wreaks havoc on horizon's keystone client,
causes different aspects of the dashboard to
timeout (e.g. project page).

    http://paste.openstack.org/show/50374/
Merge pull request #111 from blueboxgroup/blueboxgroup/disable-connection-closed

Disable haproxy http-server-close