Fix Issue #12921: BaseHTTPServer's send_error should send the correct error
response message when  send_error includes a message in addition to error
status. Patch contributed by Karl.
diff --git a/Lib/http/server.py b/Lib/http/server.py
index 5569037..22fc035 100644
--- a/Lib/http/server.py
+++ b/Lib/http/server.py
@@ -421,7 +421,7 @@
         # using _quote_html to prevent Cross Site Scripting attacks (see bug #1100201)
         content = (self.error_message_format %
                    {'code': code, 'message': _quote_html(message), 'explain': explain})
-        self.send_response(code, message)
+        self.send_response(code, shortmsg)
         self.send_header("Content-Type", self.error_content_type)
         self.send_header('Connection', 'close')
         self.end_headers()