Make recheck and reverify synonymous

* modules/openstack_project/files/zuul/layout-dev.yaml
* modules/openstack_project/files/zuul/layout.yaml: With the
freshness checks now in place, the circumstances under which recheck
vs. reverify are useful is less clear-cut and the eventual outcome
of either is basically the same. Go ahead and just make them work
the same in all circumstances to reduce developer confusion.

Change-Id: Ifbb5c67894cb436b11f69aff2d9da1140dcdaa55
Merge "Make recheck and reverify synonymous"