[Test] Make registryconnector_test.go poll the registry and remove hard-coded registry address

[rafaelsbz]

The integration tests for the Registry Connector assumes there's an instance of the registry running on localhost:8080 and skips if there isn't. This can be improved in two ways:

1. Poll the registry for a predefined ammount of time (i.e., one minute) and then either fail or skip these tests
2. Use pazuzu_config to get the registry address instead of having it hard coded. This depends on #166

[huseyz]

With removal of other registries and API change we removed this tests. I think we can close this