Fix test logging propagation

When running tests with child processes the logs from child processes
would propagate to root logger, potentially resulting in some logs
being emitted twice. Fix this by disabling log propagation to parent
loggers in child processes.

Change-Id: I31eb265c2b7f7bceff627043956a67d6def3da2b
Signed-off-by: juraj.linkes <juraj.linkes@pantheon.tech>

test/framework.py

@@ -379,6 +379,7 @@ class VppTestCase(unittest.TestCase):
         cls.logger = get_logger(cls.__name__)
         if hasattr(cls, 'parallel_handler'):
             cls.logger.addHandler(cls.parallel_handler)
+            cls.logger.propagate = False
         cls.tempdir = tempfile.mkdtemp(
             prefix='vpp-unittest-%s-' % cls.__name__)
         cls.stats_sock = "%s/stats.sock" % cls.tempdir