[PATCH] IPV4: Fix single-entry /proc/net/fib_trie output.

When main table is just a single leaf this gets printed as belonging to the
local table in /proc/net/fib_trie. A fix is below.

Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>