Keith Olbermann has just sued Current TV for firing him ... TMZ has learned. Keith filed the lawsuit moments ago in L.A. County Superior Court -- claiming he was wrongfully terminated from the network last Friday. Olbermann is reportedly suing for breach of contract, sabotage and disparagement. Sources tell TMZ, the lawsuit contains a reference to an email from Current TV President David Bohrman, in which Bohrman admits "the 33rd street studio [where Keith's show was filmed] is never going to be a professional facility. We are paying for a Porsche [the studio] and getting a Yugo [a notoriously crappy...