Fix HAProxy config for Nova EC2 API

EC2 API returns 400 for unauthenticated requests, making HAProxy believe
that the service is down. We'll use TCP check instead of HTTP check for
EC2 API.

Change-Id: Ide7f9390603c9893b95cacd51d468461255dcf07

manifests/loadbalancer.pp

@@ -738,7 +738,7 @@ class tripleo::loadbalancer (
     haproxy::listen { 'nova_ec2':
       bind             => $nova_ec2_bind_opts,
       options          => {
-        'option' => [ 'httpchk GET /' ],
+        'option' => [ ],
       },
       collect_exported => false,
     }