Did you follow Tesla Inc. or SpaceX on Facebook? Not anymore. In a matter of minutes, Elon Musk joined the #deleteFacebook movement and deleted the pages to both of his companies, losing 5 million followers in the process. In response to WhatsApp co-founder Brian Acton’s tweet, “It is time. #deletefacebook,” Musk tweeted, “What’s Facebook?” surely tongue-in-cheek, as the social-media giant has done business with SpaceX, which lost a $200 million satellite that Facebook aimed to put…