code: function _extractEsxBootCfgValue(data, pattern) {
          var pos = data.indexOf(pattern);
          if (pos >= 0) {
              pos += pattern.length;
              var lineEndPos = data.indexOf('\n', pos);
              if (lineEndPos >= 0) {
                  return data.substring(pos, lineEndPos);
              }
          }
          return '';
      }
docs: Extract the value from a whole data by key.
  @param {String} data - The whole data that cotains all key-value pairs
  @param {String} key - The key for target value including the key-value delimiter
  @return {String} The extracted value; If key is not exsited, return empty.
  @example
  // return "12xyz - pmq"
  _extractEsxiBootCfgValue("key1=abc def\nkey2=12xyz - pmq\nkey3=pmq,abq", "key2=")