remove only-non-defaulted-columns-on-insert from rails 4

rails 4 does it natively

Change-Id: I1bef20f36ca49a6afc4273794e54d68ccca27cb6
Reviewed-on: https://gerrit.instructure.com/41793
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Nick Cloward <ncloward@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>