There's only one sure thing about a career in Hollywood: You'll encounter hairpin turns at high spped, and you won't always know where you're heading.  In the last year, Brendan Fraser, 23, had gone from doing Shakespeare in Seattle to eating dog food as the mud-caked cave man in 'Encino Man' and starring in this falls' 'School Ties.'  "I guess it has worked out all right," says Fraser.  "But there's no reason for me to get lazy and think that this is going to last."