missed changing one reference of new_files to file_changes
missed changing one reference of new_files to file_changes

Change-Id: Id27ffbb08609e61a207dcab78ae480a2301a01b9
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/285238
Reviewed-by: Isaac Moore <258108225390078ef47d1319acab49ad7948abf1@instructure.com>
Reviewed-by: Spencer Olson <7cc0890d6f1f70810a023e7173eca5724d6c8e49@instructure.com>
Reviewed-by: Andrea Cirulli <b4e55ef5ee4bae8ad31f7c81009bfc0af1714a1f@instructure.com>
Reviewed-by: Ryan Norton <65299b45178f94900ff304765e8fbf07bd13b331@instructure.com>
QA-Review: James Butters <4c5a489c9bb72d41f20b3b22aaf4c9b864e32f20@instructure.com>
Product-Review: James Butters <4c5a489c9bb72d41f20b3b22aaf4c9b864e32f20@instructure.com>
Tested-by: James Butters <4c5a489c9bb72d41f20b3b22aaf4c9b864e32f20@instructure.com>

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