Terminate the long-running cat in rootwrap tests

[Thierry Carrez]

Bug 1071443 replaced the "sleep 5" call in the rootwrap KillFilter tests by a cat with stdin=PIPE stdout=PIPE stderr=STDIN that sits there doing nothing indefinitely.

While it was indeed intrducing a race condition, the sleep call had the benefit of always terminating after 5 seconds, while the "cat" process will survive until the death of the parent.

At the very minimum, we should be terminating that "cat" subprocess at the end of test_KillFilter.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/16306

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/16306
Committed: http://github.com/openstack/nova/commit/bb9fe5e0c8376488f1d907825bdd10a62d5bcb80
Submitter: Jenkins
Branch: master

commit bb9fe5e0c8376488f1d907825bdd10a62d5bcb80
Author: Davanum Srinivas <email address hidden>
Date: Fri Nov 16 09:43:55 2012 -0500

    Ensure cat process is terminated

    per bug report we should be terminating that "cat" subprocess at the
    end of test_KillFilter.

    switching from kill to terminate/wait, add try/finally to make sure we
    are ok even if an exception is thrown in between

    fixes bug #1079629

    Change-Id: I8ca767402a2bd992d4b9579615375eda0c75cb6b