How to treat trolls

Hi, I'd like to ask others for advice. As you may know, I'm maintaining the Fedora Project page at Google+. And I have a problem with a troll :) There is a guy who started posting a "WINDOWS 8 POWER!" message under every post we have on our page. It's pretty much spamming and it leads discussions on our page to unwanted directions because people of course feed the troll. I'm considering to ban him, but I don't want to do anything that would harm our reputation of open and censorship-free community. Do you think it crosses the line and banning is an appropriate reaction or should I let him be and hope that he'll stop doing it (although he can do it for months because it's nothing time taking)? Jiri