Verify that 'repositories' variable in the 'repositories' role can be used as intended

[robled]

I received a report that this functionality did not work as intended, in that if the empty (by default) 'repositories' variable is overridden via Ansible group_vars, the 'repositories' role will skip over that input data, with no error produced via Ansible. I was able to reproduce this problem in preliminary testing. I'll test this again and provide more details on the scenario.

[robled]

After further testing and discussion, it seems likely that variable precedence of group_vars included with cinch in the jenkins_slave role are overriding inputs given by users via the all group_vars file. Given that the use case here is highly likely that we want to append additional repos, we should resolve it in that way, which would mean extending the repositories role to allow for this.

[robled]

@greg-hellings - was this resolved here?

#198

[greg-hellings]

Let's just say "yes" and roll with it. I'm pretty sure this is what prompted that changeset.