OSC networking commands need to authenticate to get
service catalog, then decide to show nova-network or
neutron command help message. Fake token and fake
auth_type in prepare_to_run_command() casue os-cloud-config
use AdminToken auth plugin, but pass all the auth information
(include: username, password and so on) to it, that casue the
class initialization error. Pop the fake token and url, then
try to load auth plugin again to fix the issue.
Change-Id: I8b140f0b0a60681fc2a35a013bb0c84ff8cb9589
Closes-Bug: #1650026