spec: test classes with the same name stomp each other

TestCourseApi is also defined in another API spec, with a different set
of methods and mixins. So if you run both spec suites in the same
process, you get errors.

Change-Id: Iff4e0b4926882453821718072586b7ed02ed310a
Reviewed-on: https://gerrit.instructure.com/29266
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Stanley Stuart <stanley@instructure.com>
Product-Review: Brian Palmer <brianp@instructure.com>
QA-Review: Brian Palmer <brianp@instructure.com>