ip: fix warning on interface ipv6 prefix remove

Type: fix
Signed-off-by: Vladislav Grishenko <themiron@yandex-team.ru>
Change-Id: I428f52abbdddd9caca9b0f619a0e934f96ac0b4a
diff --git a/src/vnet/ip/ip6_forward.c b/src/vnet/ip/ip6_forward.c
index 2171cb8..7c95201 100644
--- a/src/vnet/ip/ip6_forward.c
+++ b/src/vnet/ip/ip6_forward.c
@@ -198,7 +198,7 @@
   if (!if_prefix)
     {
       clib_warning ("Prefix not found while deleting %U",
-		    format_ip4_address_and_length, address, address_length);
+		    format_ip6_address_and_length, address, address_length);
       return;
     }