fix running specs in rails 3 without development gems frd

Change-Id: I25fe977ffaaa2421b6bf1803a473b84e13a0e3e1
Reviewed-on: https://gerrit.instructure.com/30124
Reviewed-by: James Williams  <jamesw@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>