Add missing fixtures dependency to test-requirements.txt

[DennyZhang]

Fixtures are used in oslo, but missing in test-requirements.txt

./savanna/openstack/common/test.py:22:import fixtures

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/49856

[Sergey Lukjanov (slukjanov)]

We're not using sqla migrations at all, just copied by oslo-incubator update script. Fixtures should be added to the test-requirements.txt file.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/49856
Committed: http://github.com/openstack/savanna/commit/8b8df39e64f2900dda23d7e1107e17c5aded1182
Submitter: Jenkins
Branch: master

commit 8b8df39e64f2900dda23d7e1107e17c5aded1182
Author: DennyZhang <email address hidden>
Date: Sat Oct 5 15:59:57 2013 -0500

    Add missing package dependency for test_requirements.txt

    Packages of fixtures are used,
    but missing in test_requirements.txt

    Close-bug: #1235524
    Change-Id: Iab154bf420036e049c41754678e7c1b67c3bd7e6