Fix config test interaction with report_times.

In a config test, the scheduler is created without a config object.
Handle that case gracefully in the pipeline constructor.

Add a test that runs the configtest.

Change-Id: Id59b3194aff7b5347fa04fe1cc29b1069d2a3f7f
Reviewed-on: https://review.openstack.org/27585
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins