python_SUITE: Wait for the AMQP connection to close in x_queue_name.py

[Why]
I still don't know what causes the transient failures in this testsuite.
The AMQP connection is closed asynchronously, therefore the next test
case is running when it finishes to close. I have no idea if it causes
troubles, but it makes the broker logs more difficult to read.

Author: dumbbell

deps/rabbitmq_stomp/test/python_SUITE_data/src/x_queue_name.py

@@ -41,6 +41,8 @@ def test_exchange_dest(self):
 
         self.conn.disconnect()
         connection.close()
+        while not connection.is_closed:
+            time.sleep(1)
 
     def test_topic_dest(self):
         queueName='my-user-generated-queue-name-topic'
@@ -69,6 +71,8 @@ def test_topic_dest(self):
 
         self.conn.disconnect()
         connection.close()
+        while not connection.is_closed:
+            time.sleep(1)
 
 
 if __name__ == '__main__':