[NETFILTER]: nf_conntrack_ipv4: fix "Frag of proto ..." messages

Since we're now using a generic tuple decoding function in ICMP
connection tracking, ipv4_get_l4proto() might get called with a
fragmented packet from within an ICMP error. Remove the error
message we used to print when this happens.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index d9b5177..53cb177 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -87,14 +87,10 @@
 	if (iph == NULL)
 		return -NF_DROP;
 
-	/* Never happen */
-	if (iph->frag_off & htons(IP_OFFSET)) {
-		if (net_ratelimit()) {
-			printk(KERN_ERR "ipv4_get_l4proto: Frag of proto %u\n",
-			iph->protocol);
-		}
+	/* Conntrack defragments packets, we might still see fragments
+	 * inside ICMP packets though. */
+	if (iph->frag_off & htons(IP_OFFSET))
 		return -NF_DROP;
-	}
 
 	*dataoff = nhoff + (iph->ihl << 2);
 	*protonum = iph->protocol;