message: fix: cli panic
diff: @@ -10,7 +10,7 @@ pub fn get_matches() -> ArgMatches<'static> {
  .about("Nervos CKB - The Common Knowledge Base")
  .version(version.short().as_str())
  .long_version(version.long().as_str())
  - .setting(AppSettings::ArgRequiredElseHelp)
  + .setting(AppSettings::SubcommandRequiredElseHelp)
  .arg(
  Arg::with_name("config")
  .short("c")
  