Move context_managers to base class, overridden by mixed.
Move context_managers to base class, overridden by mixed.
LMS-2947 remove get_error_courses in Split.
LMS-2950 move delete_course to Mongo.
Move context_managers to base class, overridden by mixed.
LMS-2950 move delete_course to Mongo.
Fix all modulestore calls to pass in user ids.
Update tests to allow LMS tests to use published branch setting.

Conflicts:
	cms/djangoapps/contentstore/views/tests/test_container_page.py
	common/djangoapps/external_auth/tests/test_shib.py
	common/djangoapps/student/tests/test_login.py
	common/lib/xmodule/xmodule/modulestore/tests/django_utils.py
	common/lib/xmodule/xmodule/modulestore/tests/factories.py
	common/lib/xmodule/xmodule/modulestore/xml_importer.py
	lms/djangoapps/branding/tests.py
	lms/djangoapps/courseware/tests/test_submitting_problems.py
	lms/djangoapps/courseware/tests/test_video_handlers.py
	lms/djangoapps/instructor_task/tests/test_base.py
	lms/djangoapps/instructor_task/tests/test_integration.py