install gearman job server (gearmand) on zuul.o.o

fingers crossed.. we want to co-host gearman-job-server on zuul.o.o
so we can use it with the jenkins gearman plugin.

We are using the gearman puppet module from puppet forge which was
already defined in install_modules.sh

Change-Id: I45006ac14807956cb548e6538f79109a3c79e30d
Reviewed-on: https://review.openstack.org/24846
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Elizabeth Krumbach <lyz@princessleia.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins