Merge pull request #1922 from marksantcroos/master

Import secure_filename from utils.

flask_admin/form/upload.py

 import os
 import os.path as op
 
-from werkzeug import secure_filename
+from werkzeug.utils import secure_filename
 from werkzeug.datastructures import FileStorage
 
 from wtforms import ValidationError, fields

flask_admin/model/base.py

@@ -5,7 +5,7 @@ import mimetypes
 import time
 from math import ceil
 
-from werkzeug import secure_filename
+from werkzeug.utils import secure_filename
 
 from flask import (current_app, request, redirect, flash, abort, json,
                    Response, get_flashed_messages, stream_with_context)