Update fileuploads.rst

secure_filename is under werkzeug.utils (http://werkzeug.pocoo.org/docs/utils/)

docs/patterns/fileuploads.rst

@@ -22,7 +22,7 @@ bootstrapping code for our application::
 
     import os
     from flask import Flask, request, redirect, url_for
-    from werkzeug import secure_filename
+    from werkzeug.utils import secure_filename
 
     UPLOAD_FOLDER = '/path/to/the/uploads'
     ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'])