fix typo

Author: HRanjan-11

commands/utils/validate.js

@@ -57,7 +57,7 @@ module.exports = validate_config = function (lt_config, validation_configs) {
       if (!(max_duration == undefined ||
         max_duration == null ||
         isNaN(max_duration))) {
-          if (Number(parallels) && Number(parallels) % 1 !== 0){
+          if (Number(max_duration) && Number(max_duration) % 1 !== 0){
             reject("Error!! max_duration should be and Integer between 2 and 240 minutes");
           }else if (parseInt(max_duration) <2 || parseInt(max_duration) > 240){
               reject("Error!! max_duration should be between 2 and 240 minutes");