fix rails 4 route

fixes CNVS-16972

test plan
 - go to /accounts/1/account_authorization_configs
 - test ldap credentials

Change-Id: I50361b120da8ecf161778347a0e2b45be7010930
Reviewed-on: https://gerrit.instructure.com/44598
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Rob Orton <rob@instructure.com>