BFD: set per session UDP source port per RFC

Change-Id: Id294dbbd6499ae8221cc8143e1027adc08866ae6
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/src/vnet/bfd/bfd_main.h b/src/vnet/bfd/bfd_main.h
index 361ff0b..14a54d6 100644
--- a/src/vnet/bfd/bfd_main.h
+++ b/src/vnet/bfd/bfd_main.h
@@ -76,7 +76,7 @@
 #undef F
 } bfd_poll_state_e;
 
-typedef struct
+typedef struct bfd_session_s
 {
   /* index in bfd_main.sessions pool */
   u32 bs_idx;