Have zuul enqueue changes when approved

If a change had a -1 verified vote on it from jenkins zuul would not
enqueue that change for check or gate testing when that change was
approved. Zuul should enqueue the change for check testing then move it
to the gate pipeline if a verified +1 comes back from check.

Change-Id: Icdcc4878a8289a2088c85afdfc72c56d4fd3a55a
Merge "Have zuul enqueue changes when approved"