Fix unsuitable assertTrue/assertFalse in api unittest

[ZhiQiang Fan]

Some usages of assertTrue()/assertFalse() are incorrect, improve them to more explicit assert from the unit test suite (like assertIsNotNone or assertIn).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/44366

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/44366
Committed: http://github.com/openstack/neutron/commit/3ba80960075bf7873e96914f1be54ae176069a8d
Submitter: Jenkins
Branch: master

commit 3ba80960075bf7873e96914f1be54ae176069a8d
Author: ZhiQiang Fan <email address hidden>
Date: Fri Aug 30 05:35:32 2013 +0800

    Fix unsuitable assertTrue/assertFalse in api ut

    Some usages of assertTrue()/assertFalse() are incorrect, improve
    them to more explicit assert from the unit test suite.

    Closes-Bug: #1218621
    Change-Id: I22be2af05f06e91020dbaa4cf08bf395d68f563b