Added validation in the line 54 and 58 (if exist a method of that variable) because throw an error

Author: Hendry Alejandro Rodriguez Volcan

lib/logstash/inputs/protocols/ethereum.rb

@@ -51,9 +51,13 @@ def unhex(data, num_keys)
  next if value.nil? or value.kind_of?(Array)
 
  if num_keys.include? key
- data[key] = value.to_decimal()
+ if(value.methods.include? :to_decimal)
+ data[key] = value.to_decimal()
+ end
  else
- data[key] = value.to_string()
+ if(value.methods.include? :to_string)
+ data[key] = value.to_string()
+ end
  end
  end
  end