ipv4: Don't pre-seed hoplimit metric.

Always go through a new ip4_dst_hoplimit() helper, just like ipv6.

This allowed several simplifications:

1) The interim dst_metric_hoplimit() can go as it's no longer
   userd.

2) The sysctl_ip_default_ttl entry no longer needs to use
   ipv4_doint_and_flush, since the sysctl is not cached in
   routing cache metrics any longer.

3) ipv4_doint_and_flush no longer needs to be exported and
   therefore can be marked static.

When ipv4_doint_and_flush_strategy was removed some time ago,
the external declaration in ip.h was mistakenly left around
so kill that off too.

We have to move the sysctl_ip_default_ttl declaration into
ipv4's route cache definition header net/route.h, because
currently net/ip.h (where the declaration lives now) has
a back dependency on net/route.h

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index ea28fa5..04c7b3b 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -82,6 +82,7 @@
 #include <linux/tcp.h>
 
 int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
+EXPORT_SYMBOL(sysctl_ip_default_ttl);
 
 /* Generate a checksum for an outgoing IP datagram. */
 __inline__ void ip_send_check(struct iphdr *iph)
@@ -130,7 +131,7 @@
 	int ttl = inet->uc_ttl;
 
 	if (ttl < 0)
-		ttl = dst_metric_hoplimit(dst);
+		ttl = ip4_dst_hoplimit(dst);
 	return ttl;
 }