message: [trivial] fix outdated comment about max net message size
  The current maximum for the network message size is equal to:
  EB * DEFAULT_MAX_MESSAGE_SIZE_MULTIPLIER
  current value of the latter constant is 16.
diff: @@ -51,7 +51,7 @@ static const unsigned int MAX_ADDR_TO_SEND = 1000;
  /** The maximum # of bytes to receive at once */
  static const int64_t MAX_RECV_CHUNK = 256 * 1024;
  /** Maximum length of incoming protocol messages (no message over 2 MiB is currently acceptable). */
  -//static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 2 * 1024 * 1024; // BU: currently allowing 10*excessiveBlockSize as the max message
  +//static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 2 * 1024 * 1024; // BU: currently allowing DEFAULT_MAX_MESSAGE_SIZE_MULTIPLIER*excessiveBlockSize as the max message.
  /** Maximum length of strSubVer in `version` message */
  static const unsigned int MAX_SUBVERSION_LENGTH = 256;
  /** -listen default */
  