Fix synchronous reading of stream data

commit 984840a2 removed the
notification of waiting calls when VIR_NET_CONTINUE messages
arrive. This was to fix the case of a virStreamAbort() call
being prematurely notified of completion.

The problem is that sometimes there are dummy calls from a
virStreamRecv() call waiting that *do* need to be notified.

These dummy calls should have a status VIR_NET_CONTINUE. So
re-add the notification upon VIR_NET_CONTINUE, but only if
the waiter also has a status of VIR_NET_CONTINUE.

* src/rpc/virnetclient.c: Notify waiting call if stream data
  arrives
* src/rpc/virnetclientstream.c:  Mark dummy stream read packet
  with status VIR_NET_CONTINUE
(cherry picked from commit cb610092)

src/rpc/virnetclient.c

@@ -627,6 +627,15 @@ static int virNetClientCallDispatchStream(virNetClientPtr client)
     case VIR_NET_CONTINUE: {
         if (virNetClientStreamQueuePacket(st, &client->msg) < 0)
             return -1;
+
+        if (thecall && thecall->expectReply) {
+            if (thecall->msg->header.status == VIR_NET_CONTINUE) {
+                VIR_DEBUG("Got a synchronous confirm");
+                thecall->mode = VIR_NET_CLIENT_MODE_COMPLETE;
+            } else {
+                VIR_DEBUG("Not completing call with status %d", thecall->msg->header.status);
+            }
+        }
         return 0;
     }
 
@@ -1189,6 +1198,7 @@ int virNetClientSend(virNetClientPtr client,
     int ret = -1;
 
     if (expectReply &&
+        (msg->bufferLength != 0) &&
         (msg->header.status == VIR_NET_CONTINUE)) {
         virNetError(VIR_ERR_INTERNAL_ERROR, "%s",
                     _("Attempt to send an asynchronous message with a synchronous reply"));

src/rpc/virnetclientstream.c

@@ -400,6 +400,7 @@ int virNetClientStreamRecvPacket(virNetClientStreamPtr st,
         msg->header.type = VIR_NET_STREAM;
         msg->header.serial = st->serial;
         msg->header.proc = st->proc;
+        msg->header.status = VIR_NET_CONTINUE;
 
         VIR_DEBUG("Dummy packet to wait for stream data");
         virMutexUnlock(&st->lock);