Connectivity from workers to gearmand on zuul.

* manifests/site.pp: Pass both jenkins.openstack.org and
jenkins-dev.openstack.org to openstack_project::zuul as the list of
gearman workers for use in iptables rules.

* modules/openstack_project/manifests/jenkins.pp
* modules/openstack_project/manifests/jenkins_dev.pp: Remove unused
4155/tcp from public allowed ports list, previously for a bzr
service which is no longer running on these servers.

* modules/openstack_project/manifests/zuul.pp: Add iptables rules
allowing access from gearman workers to the gearmand, and also
configure gearmand to listen on all addresses including IPv6, as
opposed to its IPv4-only default.

Change-Id: I3c9c31732bcb8d4033a5ec9a602242656d993d7b
Reviewed-on: https://review.openstack.org/25583
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins