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

nova/tests/test_nova_rootwrap.py

@@ -69,6 +69,7 @@ class RootwrapTestCase(test.TestCase):
         p = subprocess.Popen(["cat"], stdin=subprocess.PIPE,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.STDOUT)
+        try:
             f = filters.KillFilter("root", "/bin/cat", "-9", "-HUP")
             f2 = filters.KillFilter("root", "/usr/bin/cat", "-9", "-HUP")
             usercmd = ['kill', '-ALRM', p.pid]
@@ -92,6 +93,10 @@ class RootwrapTestCase(test.TestCase):
             usercmd = ['kill', p.pid]
             # Providing no signal should work
             self.assertTrue(f.match(usercmd) or f2.match(usercmd))
+        finally:
+            # Terminate the "cat" process and wait for it to finish
+            p.terminate()
+            p.wait()
 
     def test_KillFilter_no_raise(self):
         """Makes sure ValueError from bug 926412 is gone"""