Reduce workers for label lookups
Reduce workers for label lookups

Using 16 causes excessive auth requests and gets us rate limited
upstream. Let's make this dynamic so that the upstream VMs will use less
workers.

Partial-Bug: #1889122
Change-Id: Ib6fed59337f3dac07264052aaf2973ec5a69504f

openstack/tripleo-common,openstack/tripleo-common