It wasn't so much the 33� temperature or the oozy quagmire; what was really bothering players like the University of Detroit's Bruce Maher last week was trying to hit a baseball that hung in falling snow like a grape in aspic. Lloyd Brazil, the Detroit coach, had succumbed to the eagerness of spring and decided his team should open its season on schedule against Albion College, in spite of Decemberish weather. As his Titans took the field, snow flurries started. Two and a half hours and seven innings later, when the game was finally called, the stuff was falling in mushy blobs, but Gary Mettie, a hot Detroit pitcher, had won himself a no-hitter. How? When his team batted he slipped into a nearby building to keep warm.