--- a/mercurial/scmutil.py	Fri Jun 30 03:42:22 2017 +0200
+++ b/mercurial/scmutil.py	Fri Jun 30 03:42:23 2017 +0200
@@ -982,14 +982,14 @@
     """helper function to know if a repo should be created as general delta
     """
     # experimental config: format.generaldelta
-    return (ui.configbool('format', 'generaldelta', False)
+    return (ui.configbool('format', 'generaldelta')
             or ui.configbool('format', 'usegeneraldelta', True))
 
 def gddeltaconfig(ui):
     """helper function to know if incoming delta should be optimised
     """
     # experimental config: format.generaldelta
-    return ui.configbool('format', 'generaldelta', False)
+    return ui.configbool('format', 'generaldelta')
 
 class simplekeyvaluefile(object):
     """A simple file with key=value lines