spec: fix ApplicationController specs rails3

- include does not check for "self" anymore
- we don't need complete_request_uri in rails3

Change-Id: Ifee1885056f0b84d80566ed15730a5359e502a51
Reviewed-on: https://gerrit.instructure.com/29772
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Ryan Florence <ryanf@instructure.com>
QA-Review: Ryan Florence <ryanf@instructure.com>