Fix FIB initialization in UDP input

Change-Id: I7c88ada2af039aa0861fe7c71361a293b999d0c7
Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>
diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c
index 591dc53..e42f9fa 100644
--- a/src/vnet/udp/udp_input.c
+++ b/src/vnet/udp/udp_input.c
@@ -206,6 +206,7 @@
 		  child0->c_lcl_port = udp0->dst_port;
 		  child0->c_rmt_port = udp0->src_port;
 		  child0->c_is_ip4 = is_ip4;
+		  child0->c_fib_index = tc0->fib_index;
 
 		  if (session_stream_accept (&child0->connection,
 					     tc0->s_index, 1))