reset sis_source_id for cloned group sets
reset sis_source_id for cloned group sets

closes #COMMS-1519

Change-Id: I32285329c9c4fa560c4ed47dc003ffb62ccc60f8
Reviewed-on: https://gerrit.instructure.com/169979
Tested-by: Jenkins
Reviewed-by: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
QA-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
Product-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>

instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms