cinder_driver_certs.sh always passes driver

[Ryan McNair]

In cinder_driver_certs.sh, the exit code from "./tools/pretty_tox.sh api.volume 2>&1 | tee -a $TEMPFILE", is tested, but this only checks that "tee" ran properly. Even if tests fail, as long as tee exits with status code zero it will say the driver passed.

Example:
FAILED (failures=27, skipped=2)

========================================================
03/06/14/18:51:40:CONGRATULATIONS!!! Device driver PASSED!,
========================================================

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/78858

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/78858
Committed: https://git.openstack.org/cgit/openstack-dev/devstack/commit/?id=0ebf2dfe62b094b1c7e507c75794dbef2bf250cd
Submitter: Jenkins
Branch: master

commit 0ebf2dfe62b094b1c7e507c75794dbef2bf250cd
Author: Ryan McNair <email address hidden>
Date: Fri Mar 7 05:31:56 2014 +0000

    cinder_driver_certs.sh always passes driver

    In cinder_driver_certs.sh, the tests are run and output is
    piped to "tee". Currently, checking the exit code of this
    command only checks that "tee" exited properly. Using the
    pipefail option for this script will ensure the entire
    pipe succeeds before passing a driver.

    Change-Id: I58311aa0e2c779467d39c4477c4ea39d14eda207
    Closes-Bug: #1289129