Merge branch 'hotfix-1.1.5'

Author: John Simons

src/NServiceBus.RabbitMQ/RabbitMqDequeueStrategy.cs

@@ -63,7 +63,8 @@ public void Init(Address address, TransactionSettings transactionSettings, Func<
         public void Start(int maximumConcurrencyLevel)
         {
             tokenSource = new CancellationTokenSource();
-            countdownEvent = new CountdownEvent(maximumConcurrencyLevel);
+            // We need to add an extra one because if we fail and the count is at zero already, it doesn't allow us to add one more.
+            countdownEvent = new CountdownEvent(maximumConcurrencyLevel + 1);
 
             for (var i = 0; i < maximumConcurrencyLevel; i++)
             {
@@ -82,6 +83,7 @@ public void Stop()
             }
 
             tokenSource.Cancel();
+            countdownEvent.Signal();
             countdownEvent.Wait();
         }