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

playbooks/base-test/post.yaml

@@ -1,6 +1,7 @@
 - hosts: all
   roles:
     - fetch-output
+    - merge-output-to-logs
 
 - hosts: all
   # NOTE(pabelanger): We ignore_errors for the following tasks as not to fail