Pulp 2.3: Updating code and tests for pulp 2.3 support

Also had to fix a few problems with the minitests and the repository in
test/fixtures/test_repos.
Pulp 2.3: Updating cassettes
Fixing repositories api controller test
Pulp 2.3: Updating spec file for new runcible version
Merge pull request #3015 from daviddavis/pulp-2.3

Pulp 2.3 support