ipvs: ratelimit flooding message in wrr scheduler

When all backends are removed from wrr scheduler by a monitoring agent, this
message can flood so fast that a 10s watchdog would reset the system.

Signed-off-by: Siim Po~der <siim@p6drad-teel.net>
--- linux-2.6.24/net/ipv4/ipvs/ip_vs_wrr.c	2008-01-24 22:58:37.000000000 +0000
+++ linux-2.6.24-ipvs_patches/net/ipv4/ipvs/ip_vs_wrr.c	2008-05-06 16:17:17.790662800 +0000
@@ -169,7 +169,7 @@
 				 */
 				if (mark->cw == 0) {
 					mark->cl = &svc->destinations;
-					IP_VS_INFO("ip_vs_wrr_schedule(): "
+					IP_VS_DBG_RL("ip_vs_wrr_schedule(): "
 						   "no available servers\n");
 					dest = NULL;
 					goto out;