rails3: fix override timestamps

Change-Id: I5647ecdad8023dad1d5e463c6dbb8e2e1b927d33
Reviewed-on: https://gerrit.instructure.com/30856
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>
QA-Review: Cameron Matheson <cameron@instructure.com>