Make direct call to controller in test_console_auth_tokens

In API unit testing, making call through WSGI is little bit overhead,
wherever applicable, unit tests can make direct call to controller
methods.

Some unit tests needs WSGI call to tests more than one plugin together.

This patch makes above cleanup in test_console_auth_tokens.

Partially implements blueprint v2-on-v3-api

Change-Id: If70b6b63caf6a167ae8b158fd76c98ac7197a524
Merge "Make direct call to controller in test_console_auth_tokens"