In multi-Ndb WakeupHandler, reset woken flag.

This had been commented out.
It is a necessary (but maybe not sufficient) part of the fix for bug#20351656

Author: jdduncan

storage/ndb/src/ndbapi/WakeupHandler.cpp

@@ -1,5 +1,5 @@
-/*
-   Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
+ /*
+   Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -179,7 +179,7 @@ int MultiNdbWakeupHandler::waitForInput(Ndb** _objs,
         if (isReadyToWake())  // already enough
         {
           pg.wait_for_input(0);
-          // woken = false;
+          woken = false;
           ignore_wakeups();
           ret = 0;
           break;
@@ -194,7 +194,7 @@ int MultiNdbWakeupHandler::waitForInput(Ndb** _objs,
 
       if (isReadyToWake())
       {
-        // woken = false;
+        woken = false;
         ignore_wakeups();
         ret = 0;
         break;