Chore: Remove ctlcmd and leftover envvar (#5392)

https://github.com/v2fly/v2ray-core/issues/360

infra/conf/xray.go

@@ -3,8 +3,6 @@ package conf
 import (
 	"context"
 	"encoding/json"
-	"log"
-	"os"
 	"path/filepath"
 	"strings"
 
@@ -47,8 +45,6 @@ var (
 		"dns":         func() interface{} { return new(DNSOutboundConfig) },
 		"wireguard":   func() interface{} { return &WireGuardConfig{IsClient: true} },
 	}, "protocol", "settings")
-
-	ctllog = log.New(os.Stderr, "xctl> ", 0)
 )
 
 type SniffingConfig struct {