spec: don't destroy defaultshard

Change-Id: I723874c16219a25fe9a14b851f60cd2d3cce9435
Reviewed-on: https://gerrit.instructure.com/37685
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>