message: change help text for minigui/server.py engine flag
diff: @@ -45,7 +45,8 @@ parser.add_argument(
  default="py",
  type=str,
  help="Which Minigo engine to use: \"py\" for the Python engine, or "
  - "\"tf\", \"lite\", \"remote\" for one of the C++ engines.")
  + "one of the C++ engines (run \"cc/main --helpon=factory\" for the "
  + "C++ engine list.")
  parser.add_argument(
  "--virtual_losses",
  