osdMessageQueue: This is the mirror of Heinz Junkes' earlier fix

When sending a message, if the queue is full so we have to wait, we
create a threadNode with an eventNode in it and stick it on the
sendQueue, then wait for a receiver to signal that event, waking us.
If we awoke due to a timeout but a receiver was actually waking us
up anyway (i.e. eventSent was set), we shouldn't give up.

src/libCom/osi/os/default/osdMessageQueue.cpp

@@ -207,8 +207,7 @@ mySend(epicsMessageQueueId pmsg, void *message, unsigned int size,
 
         freeEventNode(pmsg, threadNode.evp, status);
 
-        if ((pmsg->full && (ellFirst(&pmsg->receiveQueue) == NULL)) ||
-            status != epicsEventOK) {
+        if (pmsg->full && (ellFirst(&pmsg->receiveQueue) == NULL)) {
             epicsMutexUnlock(pmsg->mutex);
             return -1;
         }