Revert "Use rabbit_host parameter"

This reverts commit 3e419bc834.

This commit actually added a duplicate parameters that caused
duplicate resource definitions.

manifests/compute.pp

@@ -38,7 +38,6 @@ class openstack::compute(
     rabbit_userid      => $rabbit_user,
     rabbit_password    => $rabbit_password,
     image_service      => 'nova.image.glance.GlanceImageService',
-    rabbit_host        => $rabbit_host,
     glance_api_servers => $glance_api_servers,
     verbose            => $verbose,
   }