Paperclip uses backwards-compatible URLs

:fork_and_knife:

We're not going to re-upload every cookbook currently stored on S3, so we need to make sure that Paperclip generates URLs the same way as before. I've setup the non-S3 configuration to contain the S3 path, and added a test to make sure this path uses the old CookbookVersion ID if it's present. 

After running the import locally and configuring Paperclip to generate S3 URLs, imported CookbookVersion tarball URLs are identical to their community site counterparts.