bpo-35907, CVE-2019-9948: urllib rejects local_file:// scheme (GH-13474)

CVE-2019-9948: Avoid file reading as disallowing the unnecessary URL
scheme in URLopener().open() and URLopener().retrieve()
of urllib.request.

Co-Authored-By: SH <push0ebp@gmail.com>
diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index 230ac39..9b21afb 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -1745,7 +1745,7 @@
         name = 'open_' + urltype
         self.type = urltype
         name = name.replace('-', '_')
-        if not hasattr(self, name):
+        if not hasattr(self, name) or name == 'open_local_file':
             if proxy:
                 return self.open_unknown_proxy(proxy, fullurl, data)
             else: