fix bullet_instructure gem

Change-Id: I9c975b84d8a4982a80ceae4bb6069ac34226419f
Reviewed-on: https://gerrit.instructure.com/31266
Reviewed-by: Kyle Rosenbaum <kyler@instructure.com>
Product-Review: Kyle Rosenbaum <kyler@instructure.com>
QA-Review: Kyle Rosenbaum <kyler@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>