configitems: register the 'web.accesslog' config

mercurial/configitems.py

@@ -582,6 +582,9 b" coreconfigitem('ui', 'verbose',"
 coreconfigitem('verify', 'skipflags',
     default=None,
 )
+coreconfigitem('web', 'accesslog',
+    default='-',
+)
 coreconfigitem('worker', 'backgroundclose',
     default=dynamicdefault,
 )

mercurial/hgweb/server.py

@@ -282,7 +282,7 b' class MercurialHTTPServer(_mixin, httpse'
             prefix = '/' + prefix.strip('/')
         self.prefix = prefix
 
-        alog = openlog(ui.config('web', 'accesslog', '-'), ui.fout)
+        alog = openlog(ui.config('web', 'accesslog'), ui.fout)
         elog = openlog(ui.config('web', 'errorlog', '-'), ui.ferr)
         self.accesslog = alog
         self.errorlog = elog