mail: upate feed_mail command for django 1.11 (#31474)

welco/sources/mail/management/commands/feed_mail.py

@@ -23,17 +23,14 @@ from django.core.management.base import BaseCommand, CommandError
 from ...models import Mail
 
 class Command(BaseCommand):
-    args = ['category', '...']
+    def add_arguments(self, parser):
+        parser.add_argument(
+                '--category', metavar='CATEGORY', default=None)
+        parser.add_argument('filenames', metavar='FILENAME', nargs='+')
 
-    option_list = BaseCommand.option_list + (
-            make_option('--category',
-                        dest='category',
-                        default=None),
-            )
-
-    def handle(self, *args, **kwargs):
+    def handle(self, filenames, *args, **kwargs):
         count = 0
-        for filepath in args:
+        for filepath in filenames:
             if not os.path.exists(filepath):
                 continue
             if not open(filepath).read(5) == '%PDF-':