Actually get the traceparent from debuginfo instead of trace_id

Signed-off-by: Steven Woods <[email protected]>

ocaml/forkexecd/lib/forkhelpers.ml

@@ -184,7 +184,7 @@ let safe_close_and_exec ?env stdin stdout stderr
         List.fold_left maybe_add_id_to_fd_map dest_named_fds predefined_fds
       in
 
-      let env = match env with Some e -> e | None -> default_path_env_pair in
+      let env = Option.value ~default:default_path_env_pair env in
       let syslog_stdout =
         match syslog_stdout with
         | NoSyslogging ->

ocaml/xapi-idl/lib/debuginfo.ml

@@ -66,10 +66,9 @@ let with_dbg ?(with_thread = false) ~module_name ~name ~dbg f =
   | false ->
       f_with_trace ()
 
-let span_context_of_di di =
-  Option.map (fun span -> Tracing.Span.get_context span) di.tracing
-
 let traceparent_of_dbg dbg =
-  of_string dbg
-  |> span_context_of_di
-  |> Option.map Tracing.SpanContext.trace_id_of_span_context
+  match String.split_on_char separator dbg with
+  | [_; traceparent] ->
+      Some traceparent
+  | _ ->
+      None