lxc: Change VIR_ERROR to VIR_DEBUG for just a debugging message

The message is actually not of error but of debugging.
02:22:56.091: error : lxcControllerMain:316 : monitor=3 client=4 appPty=19 contPty=7

src/lxc/lxc_controller.c

@@ -313,7 +313,10 @@ static int lxcControllerMain(int monitor,
     fdArray[0].active = 0;
     fdArray[1].fd = contPty;
     fdArray[1].active = 0;
-    VIR_ERROR(_("monitor=%d client=%d appPty=%d contPty=%d"), monitor,client, appPty, contPty);
+
+    VIR_DEBUG("monitor=%d client=%d appPty=%d contPty=%d",
+              monitor, client, appPty, contPty);
+
     /* create the epoll fild descriptor */
     epollFd = epoll_create(2);
     if (0 > epollFd) {