Pass openstackwatch swift creds through to gerrit.

* modules/openstack_project/manifests/review.pp
* modules/openstack_project/manifests/review_dev.pp: Provide a
missing conduit for openstackwatch swift credentials from the global
site.pp through to the openstack_project::gerrit class.

Change-Id: Ie89c3e098323216373c0b3aecfd7e3f9993fc18e
Reviewed-on: https://review.openstack.org/25357
Reviewed-by: Anita Kuno <akuno@lavabit.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins