Ensure cat process is terminated
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

n0ano/ganttclient