Well I suppose it has the song.... Otherwise, this is a really poor and tawdry sequel to "Saturday Night Fever" that took six years to come to fruition. Quite why anyone but the accountant thought this was a good idea is anyone's guess - but John Travolta reprises his role as "Tony", this time trying to make it onto the Broadway stage. He's a changed man - he holds off on the booze, speaks poshly - hell, he even…