Document decision to use panic

I am no 100% sure but I think we can only write the HTTP status
code once. So once the 200 is out, we might as well panic on errors.
The Go HTTP server will only let the goroutine crash, not the entire
server process.

main.go

@@ -114,7 +114,7 @@ func handle_get_info_refs(user string, _ string, path string, w http.ResponseWri
 		}
 		w.Header().Add("Content-Type", fmt.Sprintf("application/x-%s-advertisement", rpc))
 		no_cache(w)
-		w.WriteHeader(200)
+		w.WriteHeader(200) // Don't bother with HTTP 500 from this point on, just panic
 		if err := pkt_line(w, fmt.Sprintf("# service=%s\n", rpc)); err != nil {
 			panic(err)
 		}
@@ -176,7 +176,7 @@ func handle_post_rpc(user string, rpc string, path string, w http.ResponseWriter
 
 	w.Header().Add("Content-Type", fmt.Sprintf("application/x-%s-result", rpc))
 	no_cache(w)
-	w.WriteHeader(200)
+	w.WriteHeader(200) // Don't bother with HTTP 500 from this point on, just panic
 	if _, err := io.Copy(w, stdout); err != nil {
 		panic(err) // No point in sending 500 to the client
 	}