Handle failed jobs with no results.

If we get a WORK_FAIL or WORK_EXCEPTION with no preceding WORK_DATA
packet with a result, record the result as LOST.

This can happen if Jenkins encounters an exception while running
the job.

Change-Id: I159248e228af4e67ba6c88282346f366592e0d37
Reviewed-on: https://review.openstack.org/32814
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins