clear all roles, not just ActiveRecord::Base
clear all roles, not just ActiveRecord::Base

Change-Id: Ibf3501f1ff1c9e8514dc9ff3a665816434386842
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/292302
Reviewed-by: Jacob Burroughs <8ecea6e385af5cf9f53123f5ca17fb5fd6a6d4b2@instructure.com>
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
QA-Review: Aaron Ogata <11ccf682c06d1508642f943a3962a1c3d00b8e44@instructure.com>
Product-Review: Aaron Ogata <11ccf682c06d1508642f943a3962a1c3d00b8e44@instructure.com>

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