sage -package download: Fix argparse for --no-check-certificate

Author: Matthias Koeppe

build/sage_bootstrap/cmdline.py

@@ -292,7 +292,7 @@ def make_parser():
     parser_download.add_argument(
         '--on-error', choices=['stop', 'warn'], default='stop',
         help='What to do if the tarball cannot be downloaded')
-    parser.add_argument(
+    parser_download.add_argument(
         '--no-check-certificate', action='store_true',
         help='Do not check SSL certificates for https connections')