Restore Gerrit's local git replication.

* modules/openstack_project/manifests/gerrit.pp: Pass the local git
replication variable through to the gerrit module.

Change-Id: I58680c00687450876c54e17378b2daaf4e438b50
Reviewed-on: https://review.openstack.org/31090
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Elizabeth Krumbach Joseph <lyz@princessleia.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins