Since Ansible host inventory globs match against both host names and
host groups, use the zuul-scheduler group when referring to
zuul01.openstack.org and similarly-named hosts so as to avoid
inadvertently matching all members of the "zuul" host group with
zuul* (which includes the executors and mergers). Continue to match
zuulv3.openstack.org separately for now as it's not in the
zuul-scheduler group (and soon to be deleted anyway).
Change-Id: I3127d121ea344e1eb37c700d37f873e34edbb86e