spec: be tolerant of non-empty jobs db

refs CNVS-10467, fixes a travis-ci failure.

Change-Id: I220b07b5cdd7b15fccea4fa4388345e645953161
Reviewed-on: https://gerrit.instructure.com/29010
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Bryan Madsen <bryan@instructure.com>
QA-Review: Bryan Madsen <bryan@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>