Adjust role::zuul::labs

Migrating Gerrit/Jenkins/Zuul to be all on the same instance
(integration-dev.eqiad.wmflabs) so we can reasonably use 127.0.0.1
everywhere.

The Zuul git repositories are local to the instance for now at
/srv/zuul/git.  Should be moved under /data/project whenever we have the
'jenkins' and 'zuul' users created on the NFS server (bug 64868).

Change-Id: I220dfde6a65742114e290942694c151b93c33b53
Merge "Adjust role::zuul::labs" into production