972744 - make the API calls to Katello on behalf of the current user

By default, admin user was always used.
Merge pull request #13 from iNecas/bz/972744

972744 - make the API calls to Katello on behalf of the current user
Make sure the tests are independent

In some order the settings_test was failing
Merge pull request #15 from iNecas/tests-independence

Make sure the tests are independent
Setting#create! is now preferred way of creatting setting records