Allow option for data not to be json encoded

I have been working on a way to upload recipes via the chef api using pychef and I have been successful. However, when uploading files to the sandbox, I cannot have data be json encoded. This is the fix I did, and should not break the way it is being used now, just adds the option to not have data be json encoded. If there is a cleaner way I am all for it, this is just how I got it working now.