Description of problem:
Can't list user roles using API
Steps to Reproduce:
1. Using WebUI, assign some roles to the user (in Administer->Users-><user>->Roles)
2. curl -H "Content-Type:application/json" -H "Accept:application/json,version=2" -k -u <user>:<password> -X GET localhost/katello/api/users/testlogin/roles
List of the assigned roles
Since this issue was entered in Red Hat Bugzilla, the release flag has been
set to ? to ensure that it is properly evaluated for this release.
GET /api/v2/users/USERNAME provides this information in the roles node.