[NETFILTER]: nf_conntrack: move registration of __nf_ct_attach

Move registration of __nf_ct_attach to nf_conntrack_core to make it usable
for IPv6 connection tracking as well.

Signed-off-by: Yasuyuki Kozakai <[e-mail]>
Signed-off-by: Patrick McHardy <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c

···
 		goto cleanup_localinops;
 	}
 #endif
-
-	/* For use by REJECT target */
-	ip_ct_attach = __nf_conntrack_attach;
-
 	return ret;
 
  cleanup:
 	synchronize_net();
-	ip_ct_attach = NULL;
 #ifdef CONFIG_SYSCTL
  	unregister_sysctl_table(nf_ct_ipv4_sysctl_header);
  cleanup_localinops:

net/netfilter/nf_conntrack_core.c

···
 {
 	int i;
 
+	ip_ct_attach = NULL;
+
 	/* This makes sure all current packets have passed through
 	   netfilter framework.  Roll on, two-stage module
 	   delete... */
···
         for (i = 0; i < PF_MAX; i++)
 		nf_ct_l3protos[i] = &nf_conntrack_generic_l3proto;
         write_unlock_bh(&nf_conntrack_lock);
+
+	/* For use by REJECT target */
+	ip_ct_attach = __nf_conntrack_attach;
 
 	/* Set up fake conntrack:
 	    - to never be deleted, not in any hashes */