fix cas spec

Change-Id: I6c6b94da276f359cf803d3290b6c8c1b82b96ebb
Reviewed-on: https://gerrit.instructure.com/35298
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Brian Palmer <brianp@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>