rpc: push ref acquisition into RPC dispatch function

There's no reason why the virNetServerClientDispatchRead method needs to
acquire an extra reference on the "client" object. An extra reference is
only needed if the registered dispatch callback is going to keep hold of
the "client" for work in the background. Thus we can push reference
acquisition into virNetServerDispatchNewMessage.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Reviewed-by: NJim Fehlig <jfehlig@suse.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/rpc/virnetserver.c

@@ -217,9 +217,11 @@ static int virNetServerDispatchNewMessage(virNetServerClientPtr client,
             priority = virNetServerProgramGetPriority(prog, msg->header.proc);
         }
 
+        virObjectRef(client);
         ret = virThreadPoolSendJob(srv->workers, priority, job);
 
         if (ret < 0) {
+            virObjectUnref(client);
             VIR_FREE(job);
             virObjectUnref(prog);
         }

src/rpc/virnetserverclient.c

@@ -1315,12 +1315,10 @@ static void virNetServerClientDispatchRead(virNetServerClientPtr client)
 
         /* Send off to for normal dispatch to workers */
         if (msg) {
-            virObjectRef(client);
             if (!client->dispatchFunc ||
                 client->dispatchFunc(client, msg, client->dispatchOpaque) < 0) {
                 virNetMessageFree(msg);
                 client->wantClose = true;
-                virObjectUnref(client);
                 return;
             }
         }