[PATCH 4 of 6] workingctx: use node.wdirid constant

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1434978310 -32400
#      Mon Jun 22 22:05:10 2015 +0900
# Node ID d1cba8551345ecb42c4e4ca235b6cd0e40055f31
# Parent  858caee64050c937be4ff2f38e23b9d6c039feba
workingctx: use node.wdirid constant

diff --git a/mercurial/context.py b/mercurial/context.py
--- a/mercurial/context.py
+++ b/mercurial/context.py
@@ -5,7 +5,7 @@
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
-from node import nullid, nullrev, short, hex, bin
+from node import nullid, nullrev, wdirid, short, hex, bin
 from i18n import _
 import mdiff, error, util, scmutil, subrepo, patch, encoding, phases
 import match as matchmod
@@ -1339,7 +1339,7 @@ class workingctx(committablectx):
         return self._repo.dirstate[key] not in "?r"
 
     def hex(self):
-        return "ff" * 20
+        return hex(wdirid)
 
     @propertycache
     def _parents(self):