Consider moving path prefix from Managers to Client?

[jistr]

See #1 (comment)

We have to also consider whether e.g. v2 client will sometimes want to access URLs that are not scoped under /v2/.

[jistr]

It's also worth menitoning that user of the Python API should not get affected by this issue. All the URL/port information will be fetched from Keystone, not passed in by the user of tuskarclient. The client creation and workflow should look roughly like this:

from tuskarclient import client
tuskar = client.get_client('v1', **auth_info)
tuskar.racks.list() # etc...