public void printWarn(String warn) {
      printWarn(warn, null);
    }
Logs warn into the log file, and if the LogHelper is not silent then into the HiveServer2 or
HiveCli info stream too.
BeeLine uses the operation log file to show the logs to the user, so depending on the
BeeLine settings it could be shown to the user.
@param warn The log message
ql/src/java/org/apache/hadoop/hive/ql/session/SessionState.java