Fix test.

tests/python/test_dmatrix.py

@@ -75,7 +75,7 @@ def test_slice(self):
         X = rng.randn(100, 100)
         y = rng.randint(low=0, high=3, size=100)
         d = xgb.DMatrix(X, y)
-        fw = rng.randn(100)
+        fw = rng.uniform(100)
         d.feature_weights = fw
 
         eval_res_0 = {}