test_amqp_log_source randomly failing

That seems to happen because of longer round trip time "python - amqp - python". This should solve the problem even for slower machines:

diff --git a/tests/logs_unittest.py b/tests/logs_unittest.py
index a9977b3..87981ce 100644
--- a/tests/logs_unittest.py
+++ b/tests/logs_unittest.py
@@ -274,9 +274,8 @@ class PythonAMQPLogTestCase(unittest.TestCase):
                 if self.stop_on_timeout:
                     raise StopIteration()

- logsource = _AMQPLogSource('oq.testlogger.#', timeout=0.1)
+ logsource = _AMQPLogSource('oq.testlogger.#', timeout=1.0)
         logsource_thread = threading.Thread(target=logsource.run)
- logsource_thread.start()
         handler = logging.handlers.BufferingHandler(float('inf'))
         logger = logging.getLogger('oq.testlogger')
         logger.addHandler(handler)
@@ -294,6 +293,7 @@ class PythonAMQPLogTestCase(unittest.TestCase):
             )
             self.producer.publish(msg.copy(),
                                   routing_key='oq.testlogger.sublogger')
+ logsource_thread.start()
             timeout.wait()
             timeout.clear()
             # raising minimum level to make sure that info message

Pull request: https://github.com/gem/openquake/pull/667