The code to expand domain_{name,id} to {user,project}_domain_{name,id}
is flawed in that it sets a project_domain_{name,id} even if a
project_{name,id} is not set. There is a valid use case for not having
a project_{name,id} - specifically getting a domain-scoped token.
In the case where we do not set a project, check for that and don't make
further assumptions that the domain input needs to be "fixed".
Closes-Bug: #1535676
Change-Id: I825fe4bc375687208bb176bb5990c23fe87c8f9d