Remove bogus RTFREE that was added in rev 1.47. The rmx code operates

directly on the radix tree and does not hold any routing table refernces.
This fixes the reference counting problems that manifested itself as a
panic during unmount of filesystems that were mounted by NFS over an
interface that had been removed.

Supported by:	FreeBSD Foundation

sys/netinet/in_rmx.c

@@ -388,8 +388,7 @@ in_ifadownkill(struct radix_node *rn, void *xap)
 		 */
 		rt->rt_flags &= ~(RTF_CLONING | RTF_PRCLONING);
 		rtexpunge(rt);
-		RTFREE_LOCKED(rt);
-	} else
+	}
 	RT_UNLOCK(rt);
 	return 0;
 }