Fix issues with CXF Conduit re-use and tests modifying client conduits

We have some tests that are modifying the HTTPConduit on client side; in those cases a separate bus needs to be used, as the conduit is linked to the bus (one conduit per protocol) which in turn is linked to the current thread.
So any test running later on the same thread and not creating a new bus will eventually re-use the conduit, which would still have the setup for the previous test.