ipvs: Make wrr "no available servers" error message rate-limited

No available servers is more an error message than something informational. It
should also be rate-limited, else we're going to flood our logs on a busy
director, if all real servers are out of order with a weight of zero.
Signed-off-by: NSven Wegener <sven.wegener@stealer.net>
Acked-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ipvs/ip_vs_wrr.c

@@ -22,6 +22,7 @@
 
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/net.h>
 
 #include <net/ip_vs.h>
 
@@ -169,7 +170,7 @@ ip_vs_wrr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
 				 */
 				if (mark->cw == 0) {
 					mark->cl = &svc->destinations;
-					IP_VS_INFO("ip_vs_wrr_schedule(): "
+					IP_VS_ERR_RL("ip_vs_wrr_schedule(): "
 						   "no available servers\n");
 					dest = NULL;
 					goto out;