Some of the reactions to Apple’s decision to make OS X 10.9 Mavericks a free upgrade have been a little over the top, especially in relation to Windows, which we think will be just fine in this so-called “new era,” as the Cupertino company calls it. However, if we’re talking about free software, Linux certainly needs to be in the discussion. During a question and answer session at LinuxCon Europe in Edinburg on Wednesday, Linus Torvalds pointed out that Linux has been free for over two decades…