Make trustee/trustor/project searchable by ID
Make trustee/trustor/project searchable by ID

In the previous implementation, we were always including the domain
argument, which caused a lookup by name for trustee/trustor and
project. By excluding it when not necessary, we do a search by
ID in find_resources.

Change-Id: Id756aeab522b5dccb2dc6b31d137a28514b0fdf6
Closes-Bug: 1473298

openstack/python-openstackclient,dtroyer/python-openstackclient,redhat-openstack/python-openstackclient,BjoernT/python-openstackclient,dtroyer/python-openstackclient,redhat-openstack/python-openstackclient,BjoernT/python-openstackclient,openstack/python-openstackclient