configitems: register the 'format.obsstore-version' config

mercurial/configitems.py

@@ -122,6 +122,9 b" coreconfigitem('format', 'manifestcaches"
 coreconfigitem('format', 'maxchainlen',
     default=None,
 )
+coreconfigitem('format', 'obsstore-version',
+    default=None,
+)
 coreconfigitem('hostsecurity', 'ciphers',
     default=None,
 )

mercurial/obsolete.py

@@ -717,7 +717,7 b' def makestore(ui, repo):'
     """Create an obsstore instance from a repo."""
     # read default format for new obsstore.
     # developer config: format.obsstore-version
-    defaultformat = ui.configint('format', 'obsstore-version', None)
+    defaultformat = ui.configint('format', 'obsstore-version')
     # rely on obsstore class default when possible.
     kwargs = {}
     if defaultformat is not None: