configitems: change the `verify.skipflags` default value to avoid a py3 crash The revlog and LFS modules use various `&` and `&=` operations with this value, which no longer treats `None` as 0. Since nothing cares if it was actually set in the config or not, just default to 0 for simplicity.

--- a/mercurial/configitems.py	Mon Oct 10 11:28:19 2022 -0400
+++ b/mercurial/configitems.py	Tue Oct 18 19:49:31 2022 -0400
@@ -2543,7 +2543,7 @@
 coreconfigitem(
     b'verify',
     b'skipflags',
-    default=None,
+    default=0,
 )
 coreconfigitem(
     b'web',