Add ability to set staff lock from course outline

STUD-1851. @cahrens please review.

Sandbox available at http://studio.benmcmorran.m.sandbox.edx.org/course/edX/Open_DemoX/edx_demo_course
Nit: you could make lines 642-647 a helper method (passing in the locked ancestor name) and share the code with the test case below.