A few issues supporting fake:

• Original thread http://boards.4chan.org/pol/thread/118997705/oops-podesta-seeking-immunity
• Shared as an image file sized 633x821 (not an original image size by any camera)
• The image file doesn't include any related metadata
• No seach result for ["robin kellert" perkinscoie] https://duckduckgo.com/?q=%22robin+kellert%22+perkinscoie&t=ffab&ia=web
• "Kellert" can't be found in the perkinscoie site internal search

A few issues supporting real:

• Address to Percins Coie is to one of their offices
• If a leaked document, the timing would match

In my opinion, much more likely a fake. A real leak would have be leaked scanning/copying the original.