use SET LOCAL, not just SET
use SET LOCAL, not just SET

to ensure it goes away after the transaction

Change-Id: Ic616c4943ed5f360fdcf9d85383739859af17abb
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/239551
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Jeremy Stanley <b3f594e10a9edcf5413cf1190121d45078c62290@instructure.com>
Reviewed-by: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
QA-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
QA-Review: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
Product-Review: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Product-Review: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms