configitems: register the 'debug.dirstate.delaywrite' config

mercurial/configitems.py

@@ -107,6 +107,9 b" coreconfigitem('commands', 'status.verbo"
 coreconfigitem('commands', 'update.requiredest',
     default=False,
 )
+coreconfigitem('debug', 'dirstate.delaywrite',
+    default=0,
+)
 coreconfigitem('devel', 'all-warnings',
     default=False,
 )

mercurial/dirstate.py

@@ -766,7 +766,7 b' class dirstate(object):'
 
         # enough 'delaywrite' prevents 'pack_dirstate' from dropping
         # timestamp of each entries in dirstate, because of 'now > mtime'
-        delaywrite = self._ui.configint('debug', 'dirstate.delaywrite', 0)
+        delaywrite = self._ui.configint('debug', 'dirstate.delaywrite')
         if delaywrite > 0:
             # do we have any files to delay for?
             for f, e in self._map.iteritems():