Add merge-output-to-logs to base-test
Add merge-output-to-logs to base-test

Before adding it to base, add to base-test so we can test that it
works.

Depends-On: https://review.openstack.org/629571
Change-Id: Ib0875d372da2ddf47502d0bb32163ed4a79fb906

openstack-infra/project-config,openstack-infra/project-config