netns: fix net.ipv6.route.gc_min_interval_ms in netns

sysctl table was copied, all right, but ->data for net.ipv6.route.gc_min_interval_ms
was not reinitialized for "!= &init_net" case.

In init_net everthing works by accident due to correct ->data initialization
in source table.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -2630,6 +2630,7 @@ struct ctl_table *ipv6_route_sysctl_init(struct net *net)
 		table[6].data = &net->ipv6.sysctl.ip6_rt_gc_elasticity;
 		table[7].data = &net->ipv6.sysctl.ip6_rt_mtu_expires;
 		table[8].data = &net->ipv6.sysctl.ip6_rt_min_advmss;
+		table[9].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
 	}
 
 	return table;