DIRTY DANCING: HAVANA NIGHTS Nobody puts Baby in the corner. In fact, she's MIA from the ''Nights''-life altogether (Patrick Swayze will cameo). Instead, this spin-off (due in February) pairs Diego Luna (''Y Tu Mama Tambien'') and Romola Garai (''I Capture the Castle'') as a couple of star-crossed dancing machines having the time of their lives in pre-revolutionary Cuba (the film was shot in Puerto Rico). ''Before this film, the only dancing I did was in a club after having a few tequilas,'' says Luna, 23. ''But now, my salsa teachers [on set] created a monster.... I dance much better, I enjoy it, and I don't have to be drunk!''