The recent update to BOLT #4 includes failure message specifications,
which are completely orthogonal to the normal ones. Don't include
them in the gen_peer_wire_csv.
This onion_defs.h file assumes we are using 2-byte failure codes as per
the onion-failmsg-cleanup branch.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
