Removed DataConversionWarning in Normalize (scikit-learn#8712)

Author: minghui-liu

sklearn/preprocessing/data.py

@@ -1281,7 +1281,7 @@ def normalize(X, norm='l2', axis=1, copy=True, return_norm=False):
     else:
         raise ValueError("'%d' is not a supported axis" % axis)
 
-    X = check_array(X, sparse_format, copy=copy, warn_on_dtype=True,
+    X = check_array(X, sparse_format, copy=copy,
                     estimator='the normalize function', dtype=FLOAT_DTYPES)
     if axis == 0:
         X = X.T