Set Apache bind port to match haproxy listen in horizon.server.cluster

Change-Id: Ic6ce4044dbf7522c4c97d8724bf111e8f3793b88
diff --git a/horizon/server/cluster.yml b/horizon/server/cluster.yml
index 8ee48a3..a68ab12 100644
--- a/horizon/server/cluster.yml
+++ b/horizon/server/cluster.yml
@@ -10,6 +10,8 @@
   horizon:
     server:
       branding: ${_param:horizon_site_branding}
+      bind:
+        port: 8078
       plugin: {}
       session:
         engine: "cache"