Updates Changelog

Changelog

@@ -30,6 +30,15 @@ Fixes
     WorkerLostError.  This gives the result handler a chance to retrieve the
     result.
 
+* multiprocessing.Pool: Shutdown could hang if rate limits disabled.
+
+    There was a race condition when the MainThread was waiting for the pool
+    semaphore to be released.  The ResultHandler now terminates after 5
+    seconds if there still results that have not been started, but no worker
+    processes left to start them  (it needs to timeout because there could
+    still be an ack+result that we haven't consumed from the result queue. It
+    is unlikely we will receive any after 5 seconds with no worker processes).
+
 * celerybeat: Now creates pidfile even if the ``--detach`` option is not set.
 
 * eventlet/gevent: The broadcast command consumer is now running in a separate