Currently, the os_nova role's functional test involves running
openstack_tempest_gate.sh, however this runs all scenario tests and
some aren't valid since cinder does not exist in this environment.
This commit updates tests/test-nova-functional.yml to only run the
specific tempest test that we need.
Change-Id: I70bc47ca1e2b1cb1c65e30168bd0c35a6297eadc