use multiprocessing queue

Signed-off-by: Anthony Leong <aj.leong623@gmail.com>

Author: ajleong623

osbenchmark/worker_coordinator/worker_coordinator.py

@@ -604,7 +604,7 @@ def __init__(self):
         self.cluster_details = None
         self.feedback_actor = None
         self.worker_shared_states = {}
-        self.update_queue = queue.Queue()
+        self.update_queue = multiprocessing.Queue()
 
     def receiveMsg_PoisonMessage(self, poisonmsg, sender):
         self.logger.error("Main worker_coordinator received a fatal indication from load generator (%s). Shutting down.", poisonmsg.details)