diff -r ffb1d0f541f5 -r 40861b2254a5 mercurial/wireproto.py
--- a/mercurial/wireproto.py	Fri Jun 30 03:44:06 2017 +0200
+++ b/mercurial/wireproto.py	Fri Jun 30 03:44:07 2017 +0200
@@ -604,7 +604,7 @@
         return v
 
     if gd:
-        v = ui.configbool('server', 'bundle1gd', None)
+        v = ui.configbool('server', 'bundle1gd')
         if v is not None:
             return v