rails4: fix Shard#lookup with protected_attributes
rails4: fix Shard#lookup with protected_attributes

refs #CNVS-21596

Change-Id: I971a0cfeed645e8600d91fba0755da3bf0cca1ec
Reviewed-on: https://gerrit.instructure.com/57754
Tested-by: Jenkins
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Product-Review: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>
QA-Review: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>

instructure/switchman,krrg/switchman,instructure/switchman