(Image credit: Sean Gallup (Getty Images)) Remember when OpenAI created a bot that could beat humans at Dota 2 ? As PCG reported last week, that was because Elon Musk had personally called Microsoft CEO Satya Nadella to secure a massive discount on access to Azure, the company's cloud computing platform. Now a new document released thanks to the ongoing Musk vs Altman legal spat has revealed just how big that discount was: and how nervy Microsoft execs were about the whole deal, and OpenAI generally. Our story begins after OpenAI had succeeded in its Dota 2 mission, with Nadella emailing Sam Altman on 11 August 2017: "Just wanted to pass on my Congrats on the win today!" A few weeks later Altman emails Nadella , saying: Nadella then emails some of his fellow Microsoft execs: Brett Tanzer, Jason Zander, Eric Horvitz and Jason Graefe. "I know we have been on this road before," writes Nadella, referring to Microsoft's previous sweetheart deal.…