Pass roles manager to user manager

This is part of breaking a cyclical dependency where the client has a
reference to the manager but the manager has a reference to the client.

To be able to pass in an adapter to the managers we need to remove the
client specific usages of manager, including referring to other managers
via the client.

Change-Id: I8fba7ece05e33d519eb31994a072275598ba76ea
Add V2 tenant user manager tests

The cross over between the tenant manager and the user manager is not
tested. As this will be changed soon re-enforce the current behaviour.

Change-Id: Ia13a24dc0632d3fb0a5b127538117872a7dc660d
Merge "Pass roles manager to user manager"
Merge "Add V2 tenant user manager tests"