Updated openstack/openstack
Project: openstack-infra/devstack-gate  27911f42a57d678ec378806eb380e067ccbd591f
null
Extract git_fetch_at_ref

The really dense logic in the zuulification of trees is actually
hard to understand. Extracting it into a common function makes
this much easier to understand the AND and OR logic of it.

Change-Id: I96f94da8901cd94772d1910d39b48270a45f73e6